Document:

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                                                                   EXHIBIT 10.30

                       CONTRIBUTION AND ADOPTION AGREEMENT

        THIS CONTRIBUTION AND ADOPTION AGREEMENT (this "Agreement"), is made
effective as of the 13th day of December, 2000 (the "Effective Date"), by and
among MARINA DISTRICT DEVELOPMENT HOLDING CO., LLC, a New Jersey limited
liability company ("Holding"); MAC, CORP., a New Jersey corporation ("MR Sub");
and BOYD ATLANTIC CITY, INC., a New Jersey corporation ("Boyd Sub") (Holding, MR
Sub and Boyd Sub each, a "Party" and collectively, the "Parties").

                                   BACKGROUND

        A. MR Sub and Boyd Sub were the sole, equal general partners in Marina
District Development Company, a New Jersey general partnership (the "Joint
Venture").

        B. MR Sub and Boyd Sub formed, as the sole equal members (i) Marina
District Development Company, LLC, a New Jersey limited liability company
("MDDC"); and (ii) Marina District Development Holding Co., LLC ("Holding"), a
New Jersey limited liability company.

        C. On the Effective Date, the Joint Venture merged with and into MDDC
pursuant to, and in accordance with, Section 42:1-49 of the New Jersey Uniform
Partnership Act and Section 42:2B-20 of the New Jersey Limited Liability Company
Act, and a Plan of Merger adopted by the Joint Venture and MDDC (the "Merger"),
pursuant to which (i) each of MR Sub and Boyd Sub contributed to MDDC its
respective partnership interests in the Joint Venture, which such interests
were, as a result of the Merger, cancelled; and (ii) MDDC is the surviving
entity of the Merger.

        D. The Parties have agreed, among other things, and wish to memorialize
and carry out in accordance with the terms of this Agreement, that: (i) each of
MR Sub and Boyd Sub shall contribute to Holding its respective membership
interest in MDDC (collectively, the "MDDC Membership Interests"); (ii) Holding
shall adopt as its operating agreement that certain Second Amended and Restated
Joint Venture Agreement of the Partnership, dated as of August 31, 2000, by and
between MR Sub and Boyd Sub (the "Joint Venture Agreement"), as amended in
accordance with this Agreement; and (iii) MR Sub and Boyd Sub shall fulfill
their remaining obligations to Holding under the terms of the Joint Venture
Agreement, as amended, with regard to capital contributions by contributing the
capital to MDDC as designee of Holding, rather than directly to Holding.

        E. MR Sub and Boyd Sub intend that the transactions described in
Sections B through D above not effect any substantive change in the Parties'
rights and obligations as set forth in the Joint Venture Agreement.

        NOW, THEREFORE, in consideration of the foregoing premises, the mutual
promises of the Parties and other good and valuable consideration, the receipt
and sufficiency of which are hereby acknowledged by each Party to the other, the
Parties, intending to be legally bound, hereby covenant and agree as follows:

                                      TERMS

        1. INCORPORATION OF RECITALS. The recitals set forth above in Sections A
through E above are hereby incorporated into and made a part of this Agreement.

        2. CONTRIBUTION OF MDDC MEMBERSHIP INTERESTS. Each of MR Sub and Boyd
Sub hereby contributes to Holding, free and clear of all liens, pledges,
hypothecations or encumbrances of any type or nature whatsoever (collectively,
"Liens"), all of its respective MDDC Membership Interests, and Holding hereby
accepts the MDDC Membership Interests (the "Contribution"). As a result of the
Contribution, Holding is the sole member of MDDC, holding 100% of the membership
interests in MDDC.

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        3. ADOPTION OF JOINT VENTURE AGREEMENT AS OPERATING AGREEMENT. MR Sub
and Boyd Sub, in their capacity as the sole members of Holding, hereby adopt as
the operating agreement of Holding, the Joint Venture Agreement as amended in
accordance with the following (the "Operating Agreement"):

            A. Section 1.1. Section 1.1 of the Joint Venture Agreement shall be
deleted and the following Section 1.1 shall be substituted:

            "Section 1.1 Organization. The Members hereby confirm that they have
            formed and established a limited liability company (the "Company"),
            under and pursuant to the provisions of the New Jersey Limited
            Liability Company Act, N.J.S.A. 42:2B-1 et seq., as amended (the
            "LLC Act"), upon the terms and conditions set forth in this
            Agreement."

            B. Section 1.2. Section 1.2 of the Joint Venture Agreement shall be
deleted and the following Section 1.2 shall be substituted:

            "Section 1.2 Name. The name of the Company shall be Marina District
            Development Holding Co., LLC, and all business of the Company shall
            be conducted solely in such name or in such other name or names as
            the Members may mutually determine."

            C. Section 1.4. Section 1.4 of the Joint Venture Agreement shall be
deleted and the following Section 1.4 shall be substituted:

            "Section 1.4 Business of the Company. The business of the Company is
            to acquire and own the Property and to design, develop, construct,
            finance, own and operate the Facility on the Property. The purposes
            of the Company shall include the conduct of casino gaming. The
            business of the Company may be conducted through one or more
            operating subsidiaries, including but not limited to MDDC. In
            furtherance of its business, the Company shall have and may exercise
            all the powers now or hereafter conferred by the laws of the State
            of New Jersey on limited liability companies formed under the laws
            of that State, and may do any and all things related or incidental
            to its business as fully as natural persons might or could do under
            the laws of that State. One such power shall include, but shall not
            be limited to, the creation, ownership and operation of an entity to
            be utilized in connection with financing the Facility, whose board
            of directors or managers shall be appointed by the Managing Member."

            D. Section 1.9. Section 1.9 of the Joint Venture Agreement shall be
deleted and the following Section 1.9 shall be substituted:

            "Section 1.9 Duration. The Company was formed on November 21, 2000
            upon the filing of a Certificate of Formation with the New Jersey
            Department of Treasury and the Company shall continue in existence
            until dissolved and liquidated pursuant to law or any provisions of
            this Agreement."

            E. Section 1.10. The definition of "Venturer" and "Venturers" in
Section 1.10 of the Joint Venture Agreement shall be deleted and the following
shall be substituted:

            "Member" and "Members" means, individually or collectively, as
            applicable, MR Sub and Boyd Sub or any successor to either Party by
            Transfer expressly permitted by this Agreement.

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<PAGE>   3

            F. Substitution of Terms. All references in the Joint Venture
Agreement to the term or terms (A) "Venturer" or "Venturers," including
references in defined terms such as "Responding Venturer," "Defaulting
Venturer," "Managing Venturer," etc., shall be replaced with the terms "Member"
and "Members", respectively; (B) "Joint Venture" shall be replaced with the term
"Company"; and (C) "Second Amended and Restated Joint Venture Agreement" shall
be replaced with the term "Operating Agreement." For the purposes of this
Agreement, the term "Company" shall include, as appropriate, MDDC.

            G. Section 2.5. The following sentence shall be added to the end of
Section 2.5 of the Joint Venture Agreement:

            "The liability of each of MR Sub and Boyd Sub as a member of Holding
            shall be limited as set forth in the Operating Agreement, the LLC
            Act and other applicable law, as each is amended from time to time."

            H. Section 3.3(a) of the Joint Venture Agreement shall be deleted
and the following Section 3.3(a) shall be substituted:

                "(a) MR Sub has previously contributed the Property to the Joint
            Venture pursuant to Section 3.2, and concurrently therewith, Boyd
            Sub made an additional capital contribution of cash in the amount of
            $90,000,000 to the Company. From time to time, except as otherwise
            provided in this Section 3.3(a), each of the Members shall
            concurrently make equal additional capital contributions of cash
            aggregating $117,000,000 each to the Company at such time or times
            as required by the provider of the Construction Financing or at the
            time or times as the Managing Member reasonably determines necessary
            to coincide with the funding of Project Costs; provided, however,
            that if acceptable to the provider of the Construction Financing,
            each of the Members may provide all or part of such $117,000,000
            cash contribution as subordinated loans, on such terms as the
            Members may mutually determine, rather than as capital
            contributions. Notwithstanding the foregoing, if acceptable to the
            provider of Construction Financing, each Member shall be entitled to
            defer a portion of such $117,000,000 capital contribution by
            providing the Company with a standby letter of credit in the amount
            of $25,000,000 as security for its obligation to contribute such
            amount. Any such letter of credit shall be on terms and conditions
            reasonably acceptable to the Members and to the provider of the
            Construction Financing, but in any event, each such letter of credit
            shall provide that the letter of credit may be drawn if, but only
            if, the respective Member shall fail to contribute the capital
            contribution secured by such letter of credit at the time required
            by either the Managing Member or by the provider of Construction
            Financing pursuant to the express terms of the Construction
            Financing. The Parties acknowledge and agree that pursuant to the
            terms of the Construction Financing, the Company may be required to
            fund in balance contributions (the aggregate amount of such
            contributions herein referred to as "In Balance Contributions")
            based on one or more revised estimates that total Project Costs will
            be in excess of $1,035,000,000 (excluding the items set forth in
            Section 3.3(b) subparts (i), (ii) and (iii) below). In the event the
            provider of Construction Financing requires any such In Balance
            Contributions, Boyd Sub shall make such In Balance Contributions.
            For purposes of this Agreement, In Balance Contributions shall be
            considered as additional capital contributions by Boyd Sub. Upon the
            final completion of the Project in accordance with the terms hereof
            and termination of any remaining liability under each Member's
            standby letter of credit, in order to properly reflect the capital
            contributions of the Members, if any In Balance Contributions have
            been made by Boyd Sub, to the extent that any such In Balance
            Contributions were not actually needed in order to fund Project
            Costs in excess of $1,035,000,000 (excluding for purposes hereof any
            Project Costs of the type set forth in Section 3.3(b) subparts (i),
            (ii) or (iii) below, which items are not the sole responsibility of

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            Boyd Sub pursuant to the terms hereof) (a "Boyd Sub Overpayment"),
            then MRI shall cause MR Sub to reimburse Boyd Sub directly outside
            of the Company an amount equal to one-half (1/2) of the Boyd Sub
            Overpayment (the "MR Sub Reimbursement"). At such time, MR Sub's
            Capital Account shall be increased by the amount of the MR Sub
            Reimbursement, and Boyd Sub's Capital Account shall be reduced by
            the amount of such MR Sub Reimbursement. In no event shall MR Sub be
            required to make the MR Sub Reimbursement to the extent that the
            total additional capital contributions made by MR Sub pursuant to
            this Section 3.3(a), including any remaining liability under MR
            Sub's standby letter of credit, plus the amount of the MR Sub
            Reimbursement, would exceed $117,000,000.

            I. A new Section 3.3(f) shall be added to the Joint Venture
Agreement as follows:

                "(f) In the event that any provider of Construction Financing
            becomes a "defaulting lender" or a "disqualified lender" (as such
            terms are defined in the Construction Financing documents) and a
            replacement lender has not assumed the commitment of such defaulting
            lender or disqualified lender, then each Member shall fund one-half
            of the loans of such defaulting lender or disqualified lender as and
            when loans are required to be funded under the Construction
            Financing, and shall thereby assume the rights and obligations
            (other than voting rights) of such defaulting lender or disqualified
            lender. The Managing Member shall use reasonable commercial efforts
            as promptly as practicable to find an eligible assignee under the
            terms of the Construction Financing to assume the commitments of the
            defaulting lender or disqualified lender and to purchase the loans
            made by the Members as contemplated by this Section 3.3(f)."

            J. Section 7.13 shall be added to the Joint Venture Agreement as
follows:

            "Section 7.13 Consolidated Records. The books, records, reports, and
            returns contemplated by this Section 7 shall include MDDC."

            K. Section 9.1 of the Joint Venture Agreement shall be amended to
add subsection (n) as follows:

            "(n) oversee, operate and manage the Company's subsidiaries,
            including without limitation, MDDC, and take actions with respect to
            such subsidiaries as are contemplated under subsections (a)-(m)
            above."

            L. Section 9.2 of the Joint Venture Agreement shall be amended to
add subsection (r) as follows:

            "(r) Transfer (as defined in Section 11.1, below) any interest in
            any subsidiary, including MDDC, or issue any interest in such
            subsidiary, or take any action described in subsections (a)-(q),
            above, through, on behalf of or with respect to such subsidiary."

            M. Sections 11.2(c), 13.1(d) and 14.9 of the Joint Venture Agreement
are deleted in their entirety and amended to read "Intentionally Omitted".

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<PAGE>   5

         4. DIRECTION AND CONSENT WITH REGARD TO CERTAIN OBLIGATIONS.

            A. Direction and Consent With Regard to Capital Contributions.
Holding hereby authorizes and directs MR Sub and Boyd Sub, and MR Sub and Boyd
Sub hereby acknowledge and agree to comply with such authorization and
direction, as follows: whenever the Operating Agreement requires either MR Sub
or Boyd Sub to make a capital contribution to Holding, including without
limitation, the capital contributions required under Article 3 of the Operating
Agreement (to the extent not previously made to MDDC or the Joint Venture), MR
Sub or Boyd Sub, as the case may be, must and shall fulfill its obligation to
make such capital contribution by contributing the required capital to MDDC,
rather than directly to Holding. Notwithstanding the foregoing, the Parties
hereby acknowledge that the Property (as defined in the Joint Venture Agreement)
has been previously contributed by MR Sub to the Joint Venture, and pursuant to
the Merger, the Property is now held by MDDC.

            B. Authorization and Consent With Regard to Other Obligations. The
Parties hereby acknowledge and agree that whenever the Operating Agreement
establishes rights and obligations of Boyd Sub and/or MR Sub to, or with respect
to, Holding, including, without limitation, such rights and obligations
regarding: (1) the Road Development Agreement; (2) the Special Revenue Bonds;
(3) the Ordinance; (4) the Employee Parking Lot and Option regarding same; (5)
the Jobs and Business Opportunities Program; and (6) the CRDA funds (as each
such term is defined in the Operating Agreement), Holding shall have the sole
right and discretion to authorize and direct either or both of MR Sub and Boyd
Sub, and MR Sub and/or Boyd Sub, as the case may be, shall comply with such
authorization and direction, to perform or fulfill such obligations as to MDDC,
rather than directly as to Holding.

            C. Continued Responsibility For Certain Costs. The Parties hereby
acknowledge and agree that nothing in this Section 4 is intended to, and shall
not be construed to, relieve either Boyd Sub or MR Sub from any responsibility
for the payment of certain costs and expenses as specified in the Operating
Agreement, solely as the result of Holding's authorization and direction to
contribute or perform as to MDDC, rather than directly to Holding including,
without limitation, MR Sub's sole responsibility to pay all real property
transfer taxes or fees and any other costs and expenses of conveying the
Property (as defined in the Operating Agreement) to MDDC.

            D. Confirmation of Allocations. The Parties hereby acknowledge and
agree that (1) nothing set forth in this Agreement is intended to amend, revise
or alter (A) the allocation of Profits and Losses and the respective Capital
Accounts (as such terms are defined in the Operating Agreement) of MR Sub or
Boyd Sub; or (B) the special allocations set forth in Section 5.2 of the
Operating Agreement; and (2) the terms and conditions of the Operating Agreement
shall govern and prevail with respect to the allocations referenced in the
provisions of Section 4.D(1) immediately above.

         5. NO VIOLATION. The Parties hereby acknowledge and agree that nothing
in this Agreement, including Holding's authorization and direction with regard
to capital contributions set forth in Section 4A above or Holding's right to
make future directions with regard to capital contributions and the fulfillment
of performance obligations set forth in Section 4B above is in violation, or
constitutes a breach, of any provision of the Operating Agreement including,
without limitation, any provision of Section 3.4(b), Section 9.3 or Article 11.

                                        5

<PAGE>   6

         6. REPRESENTATIONS AND WARRANTIES OF MR SUB. MR Sub hereby restates and
confirms as of the Effective Date all of the representations and warranties made
by MR Sub in the Joint Venture Agreement, including but not limited to the
representations and warranties in Section 10.1 thereof. In addition, MR Sub
hereby represents and warrants to Holding and to Boyd Sub, as follows:

            A. No Further Approval. All corporate action required to be taken by
MR Sub to enter into and carry out the terms of this Agreement has been taken
and, except as otherwise provided or contemplated in this Agreement, no further
approval of any governmental agency, court or other body is necessary in order
to permit MR Sub to enter into and carry out the terms of this Agreement.

            B. Due Execution; Binding Obligation. This Agreement has been duly
executed and delivered by MR Sub and constitutes the legal, valid and binding
obligation of MR Sub, enforceable in accordance with its terms (subject to
applicable bankruptcy, insolvency, moratorium or similar laws affecting
creditors' rights generally, equitable principles and judicial discretion).

            C. No Violation. To the best of MR Sub's knowledge, neither the
execution and delivery of this Agreement, nor the performance of its obligations
hereunder, has resulted or will result in any violation of, or default under,
the certificate of incorporation or by-laws of MR Sub or any indenture, trust
agreement, mortgage or other agreement or any permit, judgment, decree or order
to which MR Sub is a party or by which it is bound and there is no default and
no event or omission has occurred which, with the passage of time or the giving
of notice or both, would constitute a default on the part of MR Sub under this
Agreement.

            D. No Proceedings. To the best of MR Sub's knowledge, there is no
action, proceeding or investigation, pending or threatened, which questions the
validity or enforceability of this Agreement as to MR Sub.

            E. No Liens. All of the MDDC Membership Interests owned by MR Sub
are currently owned, and are being contributed to Holding, free and clear of all
Liens.

         7. REPRESENTATIONS AND WARRANTIES OF BOYD SUB. Boyd Sub hereby restates
and confirms as of the Effective Date all of the representations and warranties
made by Boyd Sub in the Joint Venture Agreement, including but not limited to
the representations and warranties in Section 10.2 thereof. In addition, Boyd
Sub hereby represents and warrants to MR Sub and Holding, as follows:

            A. No Further Approval. All corporate action required to be taken by
Boyd Sub to enter into and carry out the terms of this Agreement has been taken
and, except as otherwise provided or contemplated in this Agreement, no further
approval of any governmental agency, court or other body is necessary in order
to permit Boyd Sub to enter into and carry out the terms of this Agreement.

            B. Due Execution; Binding Obligation. This Agreement has been duly
executed and delivered by Boyd Sub and constitutes the legal, valid and binding
obligation of Boyd Sub, enforceable in accordance with its terms (subject to
applicable bankruptcy, insolvency, moratorium or similar laws affecting
creditors' rights generally, equitable principles and judicial discretion).

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<PAGE>   7

            C. No Violation. To the best of Boyd Sub's knowledge, neither the
execution and delivery of this Agreement, nor the performance of its obligations
hereunder, has resulted or will result in any violation of, or default under,
the certificate of incorporation or by-laws of Boyd Sub or any indenture, trust
agreement, mortgage or other agreement or any permit, judgment, decree or order
to which Boyd Sub is a party or by which it is bound and there is no default and
no event or omission has occurred which, with the passage of time or the giving
of notice or both, would constitute a default on the part of Boyd Sub under this
Agreement.

            D. No Proceedings. To the best of Boyd Sub's knowledge, there is no
action, proceeding or investigation, pending or threatened, which questions the
validity or enforceability of this Agreement as to Boyd Sub.

            E. No Liens. All of the MDDC Membership Interests owned by Boyd Sub
are currently owned, and are being contributed to Holding, free and clear of all
Liens.

         8. RATIFICATION AND CONFIRMATION . Except as, and to the extent,
amended in accordance with the terms of this Agreement, all other provisions of
the Joint Venture Agreement are hereby ratified and confirmed by the Parties as
provisions of the Operating Agreement. To the extent that this Agreement
expressly conflicts with the Joint Venture Agreement, the terms of this
Agreement shall prevail. Notwithstanding the foregoing, it is the Parties'
intent that the transactions described in the Recitals not substantively change
the rights and obligations as set forth in the Joint Venture Agreement prior to
the date hereof.

         9. MISCELLANEOUS PROVISIONS.

            A. Amendments. The provisions of this Agreement may not be waived,
amended or repealed, in whole or in part, by any of the Parties, except with the
written consent of each of the Parties.

            B. Successors and Assigns. This Agreement shall be binding on, and
inure to the benefit of, the Parties and their respective legal representatives,
successors and permitted transferees and assigns.

            C. Severability. Each provision of this Agreement is intended to be
severable. If any term or provision hereof is held to be illegal or invalid for
any reason, such illegality or invalidity shall not affect the legality or
validity of the remainder of this Agreement.

            D. Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

            E. Entire Agreement; No Assignment. This Agreement, including the
Joint Venture Agreement as revised in accordance with the terms of this
Agreement, constitutes the complete and exclusive statement of the agreement
among the Parties with regard to its subject matter. No Party may assign its
rights or obligations under this Agreement to any other person or entity without
the prior written consent of each of the other Parties and any attempt to do so
will be null and void as of the inception and of no effect.

            F. Further Assurances. Each of the Parties agrees to perform any
further acts and execute, acknowledge and deliver any documents or instruments
which may be reasonably necessary or appropriate to carry out the provisions of
this Agreement.

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<PAGE>   8

            G. Governing Law and Choice of Forum. This Agreement shall be
governed by and construed in accordance with the laws of the State of New Jersey
without regard to its conflict of laws principles. In the event of any
litigation between or among any of the Parties concerning or arising out of this
Agreement, the Parties hereby consent to the exclusive jurisdiction of the
federal and state courts in New Jersey.

            IN WITNESS WHEREOF, the Parties have executed this Agreement as of
the Effective Date.

                                              MARINA DISTRICT DEVELOPMENT
                                                HOLDING CO., LLC

                                              By Its Members:

                                              MAC, CORP., Member

                                              By:
                                                  ------------------------------
                                                  Peter C. Walsh, Assistant
                                                  Secretary

                                              Boyd Atlantic City, Inc., Member

                                              By:
                                                  ------------------------------
                                                  Ellis Landau
                                                  Vice President, Treasurer and
                                                  Chief Financial Officer

                                              MAC, CORP.

                                              By:
                                                  ------------------------------
                                                  Peter C. Walsh, Assistant
                                                  Secretary

                                              BOYD ATLANTIC CITY, INC.

                                              By:
                                                  ------------------------------
                                                  Ellis Landau
                                                  Vice President, Treasurer and
                                                  Chief Financial Officer

                       [signatures continued on next page]

                                       8

<PAGE>   9

         Marina District Development Company, LLC, hereby acknowledges and
consents to the terms of this Agreement.

                                              Marina District Development
                                                Company, LLC

                                              By Its Members:

                                              MAC, CORP., Member

                                              By:
                                                  ------------------------------
                                                  Peter C. Walsh, Assistant
                                                  Secretary

                                              Boyd Atlantic City, Inc., Member

                                              By:
                                                  ------------------------------
                                                  Ellis Landau
                                                  Vice President, Treasurer and
                                                  Chief Financial Officer

         Each of the undersigned, Mirage Resorts, Incorporated and Boyd Gaming
Corporation, hereby (1) acknowledges and consents to the terms of this
Agreement; and (2) reaffirms the continuing existence of its respective
obligations under the Joint Venture Agreement, which obligations shall remain
unchanged by virtue of the Merger, this Agreement or any transactions
contemplated in connection with either the Merger or this Agreement.

                                              Mirage Resorts, Incorporated

                                              By:
                                                  ------------------------------
                                                  Name/Title:

                                               Boyd Gaming Corporation

                                               By:
                                                   -----------------------------
                                                   Ellis Landau
                                                   Executive Vice President,
                                                   Treasurer and Chief
                                                   Financial Officer

                                        9<PAGE>   1

                                                                   EXHIBIT 10.31

                     GUARANTY OF PERFORMANCE AND COMPLETION

     THIS GUARANTY OF PERFORMANCE AND COMPLETION (this "Completion Guaranty"),
dated as of December 13, 2000, is made by BOYD GAMING CORPORATION, a Nevada
corporation (the "Guarantor"), in favor of each of the Administrative Agent and
the Lenders and their respective successors, transferees and assigns.

                              W I T N E S S E T H:

     WHEREAS, pursuant to a Credit Agreement, dated as of even date herewith
(together with all amendments and other modifications, if any, from time to time
thereafter made thereto, the "Credit Agreement"), among Marina District Finance
Company, Inc., a New Jersey corporation (the "Borrower"), Marina District
Development Company, LLC, a New Jersey limited liability company ("MDDC"), the
various lending institutions (individually a "Lender" and collectively the
"Lenders") as are, or may from time to time become, parties thereto, the Issuing
Bank and Canadian Imperial Bank of Commerce, as administrative agent (together
with any successor(s) thereto in such capacity, the "Administrative Agent") for
the Lenders, the Lenders have extended Commitments to make Loans to the Borrower
and the Issuer has agreed to issue Letters of Credit for the account of the
Borrower; and

     WHEREAS, as a condition precedent to the effectiveness of the Credit
Agreement, the Guarantor is required to execute and deliver this Completion
Guaranty; and

     WHEREAS, the Guarantor has duly authorized the execution, delivery and
performance of this Completion Guaranty; and

     WHEREAS, it is in the best interests of the Guarantor to execute this
Completion Guaranty inasmuch as the Guarantor will derive substantial direct and
indirect benefits from the Loans made to the Borrower by the Lenders pursuant to
the Credit Agreement and the Letters of Credit issued for the account of the
Borrower under the Credit Agreement;

     NOW THEREFORE, for good and valuable consideration, the receipt of which is
hereby acknowledged, and in order to induce the Lenders to make Loans to the
Borrower and the Issuer to issue Letters of Credit for the account of the
Borrower pursuant to the Credit Agreement, the Guarantor agrees, for the benefit
of the Administrative Agent and each Lender, as follows:

1.   Definitions. Terms defined in the Credit Agreement and not otherwise
     defined in this Completion Guaranty shall have the meanings ascribed to
     them in the Credit Agreement. As used in this Completion Guaranty, the
     following terms shall have the meanings respectively set forth after each:

     "Bankruptcy Code" shall mean Title 11 of the United States Code as amended
     from time to time.

<PAGE>   2

     "Enforcement Costs" means all out-of-pocket costs and expenses of the
     Administrative Agent and the Lenders in connection with the enforcement of
     their rights and remedies under this Completion Guaranty and any amendment,
     waiver or consent relating hereto including, without limitation, reasonable
     attorneys' fees and costs and expenses, court costs and filing fees in
     addition to all other amounts due hereunder whether or not such Enforcement
     Costs are incurred in one or more proceedings.

     "Existing Senior Facility" shall mean that certain credit facility pursuant
     to that certain First Amended and Restated Credit Agreement dated as of
     June 30, 1999, among the Guarantor, as Borrower, certain commercial lending
     institutions set forth therein, as the Lenders, Administrative Agent, as
     the L/C Issuer and administrative agent, Wells Fargo Bank, N.A. as
     Swingline Lender and Syndication Agent, and Bank of America, N.A., as
     Documentation Agent as such agreement may be modified, amended, restated,
     amended and restated, supplemented, replaced, refinanced or any provision
     thereof waived. All terms of the Existing Senior Facility to which
     reference is made herein, together with all related definitions, ancillary
     provisions and related schedules, are hereby incorporated into this
     Completion Guaranty by reference as though specifically set forth in this
     Completion Guaranty. To the extent that the First Amended and Restated
     Credit Agreement described above is replaced or refinanced, any reference
     herein to a Section or Article of such First Amended and Restated Credit
     Agreement shall refer to the corresponding Section or Article of such
     replacement agreement. If the First Amended and Restated Credit Agreement
     shall be terminated and not replaced or refinanced, the term "Existing
     Senior Facility" shall refer to the First Amended and Restated Credit
     Agreement or successor Existing Senior Facility as in effect on the date of
     such termination.

     "GAAP" shall mean the generally accepted accounting principles as in effect
     from time to time in the United States.

     "Guaranteed Obligations" means the obligations of the Guarantor under
     Section 2 of this Completion Guaranty.

     "Insolvency Proceeding" shall mean any case or proceeding, voluntary or
     involuntary, under the Bankruptcy Code, or any similar existing or future
     law of any jurisdiction, foreign, state or federal, relating to bankruptcy,
     insolvency, reorganization or relief of debtors.

     "Material Adverse Effect" means (x) a material adverse effect on the
     financial condition, business or property of the Guarantor or on its
     ability to perform in all material respects its obligations under any Loan
     Document to which it is a party, (y) a material adverse effect on the
     financial condition, business, property and ability of any other Project
     Party to perform in all material respects its obligations under any Loan
     Document to which it is a party or (z) a material impairment of the
     validity or enforceability of, or a material impairment of the rights,
     remedies or benefits available to the Administrative Agent, the Issuer or
     the Lenders under any of the Loan Documents.

                                       2
<PAGE>   3

2.   Guaranty of Completion and Performance. The Guarantor absolutely,
     unconditionally and irrevocably, on the terms and subject to the conditions
     set forth herein, guarantees to the Administrative Agent and the Lenders
     that:

     (a)  until terminated as provided in Section 3 hereof, promptly after
          receipt by the Guarantor of any written notice from the Administrative
          Agent specifying any of the obligations of the Credit Parties
          specified in this clause that are not being complied with by the
          Credit Parties, the Guarantor will perform or shall cause the Credit
          Parties to perform the obligations set forth in Sections 7.1.10
          [Project Costs], 7.1.12 [Diligent Construction of the Project], 7.1.13
          [Compliance with Legal Requirements], 7.1.14 [In Balance; Borrower
          Equity], 7.1.16 [Plans and Specifications], 7.1.17 [Construction
          Consultant], 7.1.20 [Application of Insurance and Condemnation
          Proceeds], 7.1.23 [Compliance with Material Project Documents] and
          7.1.25 [Further Construction Undertakings] of the Credit Agreement;

     (b)  until terminated as provided in Section 3 hereof, promptly after
          receipt by the Guarantor of any written notice from the Administrative
          Agent specifying any of the obligations of the Credit Parties
          specified in this clause that are not being complied with by the
          Credit Parties, the Guarantor will perform or shall cause the Credit
          Parties to perform the obligations set forth in Sections 7.2.16 [Scope
          Changes] and 7.2.17 [Scope Changes and Amendments of Project Budget
          and Construction Benchmark Schedule] of the Credit Agreement;

     (c)  in the event the Guarantor shall fail or refuse to pay or perform the
          Guaranteed Obligations under this Completion Guaranty, the
          Administrative Agent may pay or perform or cause the payment and
          performance of the Guaranteed Obligations of the Guarantor hereunder
          in which case the Guarantor, upon demand by the Administrative Agent,
          shall pay any and all costs, expenses and liabilities for such costs
          and expenses in connection with the Completion of the Project as
          contemplated by the Credit Agreement, or cause any Lien in connection
          with the Completion thereof or any claim or demand for the payment of
          the cost of the Completion of the Project to be bonded, discharged,
          released or paid as contemplated by the Credit Agreement, shall
          reimburse the Administrative Agent for all sums paid and all
          reasonable costs, expenses or liabilities incurred by the
          Administrative Agent in connection therewith; and

     (d)  the Guarantor shall pay the Enforcement Costs.

3.   Continuation of Guaranty. Subject to the following sentence, this
     Completion Guaranty shall continue to be in full force and effect whether
     or not the Obligations of the Borrower under the Credit Agreement have been
     accelerated pursuant to the provisions of Section 8.2 or 8.3 thereof.
     Subject to the provisions of Section 9 hereof, provided that any
     Enforcement Costs owing hereunder have been paid, this Completion Guaranty
     shall terminate upon submission by the Guarantor of a Final Completion
     Certificate substantially in the form of Exhibit A hereto on or after the
     earliest of the following dates: (i) the Final Completion Date, so long as
     no Event of Default under and as defined

                                       3
<PAGE>   4

     in the Credit Agreement has occurred and is continuing, (ii) if an Event of
     Default under and as defined in the Credit Agreement exists on the Final
     Completion Date, the earlier of (x) the date of the cure or waiver of such
     Event of Default, and (y) the date six months after the Final Completion
     Date; provided, however, that if on such date an enforcement of a warranty
     is being pursued, then the Completion Guaranty shall continue in effect but
     only with respect to the enforcement action being pursued, and this
     Completion Guaranty shall terminate with respect to such enforcement action
     on the earlier of (A) the date of the cure of waiver of the Event of
     Default existing on the Final Completion Date and not cured or waived on
     the date six months after the Final Completion Date, and (B) the date of
     the settlement or termination of the enforcement action being pursued as of
     the date six months after the Final Completion Date, and (iii) the date on
     which all Obligations are paid in full and the Commitments have been
     terminated. Notwithstanding any other provision of this Completion
     Guaranty, from and after the Final Completion Date and payment of any
     Guaranteed Obligations owing as of such date, the Guarantor shall have no
     further obligations hereunder except for the obligation to cause MDDC to
     enforce its rights under construction warranties with respect to any
     construction defects. All amounts received by the Administrative Agent
     hereunder shall be applied by it to the satisfaction of the Guaranteed
     Obligations and in accordance with the Loan Documents.

4.   Proof of Damages. If the Guarantor shall at any time or from time to time
     fail to perform or comply with any of the Guaranteed Obligations contained
     herein and if for any reason the Administrative Agent has failed to receive
     when due and payable the payment of any amount payable by the Guarantor
     under this Completion Guaranty, then (i) it shall be assumed conclusively
     without necessity of proof that such failure by the Guarantor was the sole
     and direct cause of the Lenders failing to receive such payment when due
     irrespective of any other contributing or intervening cause whatsoever, and
     (ii) the Guarantor further irrevocably waives to the fullest extent
     permitted by law any right or defense the Guarantor may have to cause the
     Lenders to prove the cause or amount of such damages.

5.   Rights of the Administrative Agent. The Guarantor authorizes the
     Administrative Agent, on behalf of the Lenders, to perform any or all of
     the following acts at any time in its sole discretion, all without notice
     to the Guarantor and without affecting the payment and performance of the
     Guaranteed Obligations by the Guarantor:

     (a)  The Administrative Agent and the Lenders may alter any terms of the
          Loan Documents to which the Guarantor is not a party, including
          renewing, compromising, extending, enforcing or accelerating, or
          otherwise changing the time for payment of, or increasing or
          decreasing the rate of interest on, the Loans or any part of them or
          increasing or decreasing the amount of the Loans or any other fees
          payable under the Loan Documents.

     (b)  The Administrative Agent and the Lenders may take and hold security
          for the Loans, the Letters of Credit and the Borrower's other
          obligations under the Credit Agreement, and the Guaranteed Obligations
          under this Completion Guaranty, accept additional or substituted
          security for any of the foregoing, and subordinate, exchange, enforce,
          waive, release, compromise, fail to perfect and sell or otherwise
          dispose of any such security.

                                       4
<PAGE>   5

     (c)  The Administrative Agent and the Lenders may direct the order and
          manner of any sale of all or any part of any security now or later to
          be held for the Loans, the Letters of Credit, this Completion Guaranty
          or any of the other Loan Documents, and may also bid at any such sale.

     (d)  The Administrative Agent and the Lenders may apply any payments or
          recoveries from the Borrower, or any other source (other than the
          Guarantor), and any proceeds of any security, to the Borrower's
          obligations under the Loan Documents in such manner, order and
          priority as they may elect, whether or not those Obligations are
          supported by this Completion Guaranty or secured at the time of the
          application.

     (e)  The Administrative Agent and the Lenders may release the Borrower of
          its liability for the Obligations under the Credit Agreement or any
          portion thereof.

     (f)  The Administrative Agent and the Lenders may substitute, add or
          release any one or more guarantors or endorsers.

     (g)  In addition to the Obligations under the Credit Agreement, the
          Administrative Agent and the Lenders may extend other credit to the
          Borrower, its Affiliates and the Guarantor or their respective
          Affiliates and may take and hold security for the credit so extended,
          all without affecting the Guarantor's liability under this Completion
          Guaranty.

     (h)  The Administrative Agent and the Lenders may change the terms or
          conditions of disbursement of the Loans or the issuance of the Letters
          of Credit.

     (i)  The Administrative Agent and the Lenders may advance additional funds
          to the Borrower for any purpose.

6.   Completion Guaranty to be Absolute. The Guarantor expressly agrees that
     until the Final Completion Date the Guarantor shall not be released from
     the Guaranteed Obligations hereunder by or because of:

     (a)  Any act or event which might otherwise discharge, reduce, limit or
          modify the Guaranteed Obligations;

     (b)  Any waiver, extension, modification, forbearance, delay or other act
          or omission of the Administrative Agent or the Lenders, or any failure
          to proceed promptly or otherwise as against the Borrower, the
          Guarantor, MDDC or any security,

     (c)  Any action, omission or circumstance which might increase the
          likelihood that the Guarantor may be called upon to perform under this
          Completion Guaranty or which might affect the rights or remedies of
          the Guarantor as against the Borrower or MDDC; or

     (d)  Any dealings occurring at any time between the Borrower, MDDC, the
          Guarantor, the Administrative Agent or any Lender, whether relating to
          the Loans, the Letters of Credit or otherwise.

                                       5
<PAGE>   6
     The Guarantor hereby expressly waives and surrenders any defense to its
     liability under this Completion Guaranty based upon any of the foregoing
     acts, omissions, agreements, waivers or matters. It is the purpose and
     intent of this Completion Guaranty that the Guaranteed Obligations shall be
     absolute and unconditional under any and all circumstances.

7.   Guarantor's Waivers. The Guarantor waives:

     (a)  Any right it may have to require the Administrative Agent or the
          Lenders to proceed against the Borrower or MDDC, proceed against or
          exhaust any security held from the Borrower, or MDDC, or pursue any
          other remedy in their power to pursue;

     (b)  Any defense based on any claim that the Guaranteed Obligations exceed
          or are more burdensome than those of the Borrower or MDDC;

     (c)  Any defense based on: (i) any legal disability of the Borrower or
          MDDC, (ii) any release, discharge, modification, impairment or
          limitation of the liability of the Borrower and/or MDDC under the Loan
          Documents from any cause, whether consented to by the Administrative
          Agent or any Lender or arising by operation of law or from any
          Insolvency Proceeding, (iii) any rejection or disaffirmance of the
          Loans or any security held for the Loans, in any Insolvency Proceeding
          and (iv) the Guarantor's rights under applicable New Jersey law, the
          Guarantor specifically agreeing that this clause (iv) shall constitute
          a waiver of discharge under applicable New Jersey law;

     (d)  Any defense based on any action taken or omitted by the Administrative
          Agent or any Lender in any Insolvency Proceeding involving the
          Borrower or MDDC, including any election to have a claim allowed as
          being secured, partially secured or unsecured, any extension of credit
          by the Administrative Agent or any Lender to the Borrower in any
          Insolvency Proceeding, and the taking and holding by the
          Administrative Agent or any Lender of any security for any such
          extension of credit;

     (e)  All presentments, demands for performance, protests, notices of
          protest, notices of dishonor, notices of acceptance of this Completion
          Guaranty and of the existence, creation, or incurring of new or
          additional indebtedness, and demands and notices of every kind;

     (f)  Any defense based on or arising out of any defense that the Borrower
          or MDDC may have to the payment or performance of the Obligations
          under the Credit Agreement or any portion of such Obligations; and

     (g)  Any defense or benefit based on applicable New Jersey law and judicial
          decisions relating thereto and applicable New Jersey law and judicial
          decisions relating thereto.

                                       6

<PAGE>   7
8.   Waivers of Subrogation and Other Rights.

     (a)  Upon the occurrence and during the continuance of any Event of
          Default, the Administrative Agent in its sole discretion (except where
          the consent of all Lenders or Required Lenders is otherwise required
          pursuant to the Loan Documents), without prior notice to or consent of
          the Guarantor, may elect to: (i) foreclose either judicially or
          nonjudicially against any real or personal property security for the
          Obligations under the Loan Documents, (ii) accept a transfer of any
          such security in lieu of foreclosure, (iii) compromise or adjust the
          Loans or any part thereof or any of the Letters of Credit or make any
          other accommodation with the Borrower, MDDC or the Guarantor, or (iv)
          exercise any other remedy against the Borrower, MDDC or any security.
          No such action by the Administrative Agent or any Lender shall release
          or limit the liability of the Guarantor, who shall remain liable under
          this Completion Guaranty after the action, even if the effect of the
          action is to deprive the Guarantor of any subrogation rights, rights
          of indemnity, or other rights to collect reimbursement from the
          Borrower or MDDC for any sums paid to the Administrative Agent or the
          Lenders, whether contractual or arising by operation of law or
          otherwise. The Guarantor expressly waives any defenses or benefits
          that may be derived from applicable New Jersey law and judicial
          decisions relating thereto, or provisions of New Jersey law which are
          comparable to California Civil Procedure Sections 580a, 590b, 580d, or
          726 or comparable provisions of the laws of any other jurisdiction,
          and all other suretyship defenses they otherwise might or would have
          under New Jersey law or other applicable law. The Guarantor expressly
          agrees that under no circumstances shall it be deemed to have any
          right, title, interest or claim in or to any real or personal property
          to be held by the Administrative Agent or any Lender or any third
          party after any foreclosure or transfer in lieu of foreclosure of any
          security for the Obligations under the Credit Agreement.

     (b)  Regardless of whether the Guarantor may have made any payments to the
          Administrative Agent or any Lender, the Guarantor hereby waives: (i)
          all rights of subrogation, all rights of indemnity; and any other
          rights to collect reimbursement from the Borrower or MDDC for any sums
          paid to the Administrative Agent or any Lender, whether contractual or
          arising by operation of law (including the Bankruptcy Code) or
          otherwise, (ii) all rights to enforce any remedy that the
          Administrative Agent or any Lender may have against the Borrower or
          MDDC or any other Person, and (ii) all rights to participate in any
          security now or later to be held by the Administrative Agent or any
          Lender for the Obligations under the Credit Agreement. The waivers
          given in this Section 8(b) shall be effective until the Loans and all
          other Obligations under the Credit Agreement have been indefeasibly
          paid and performed in full and all Commitments have been terminated.

                                       7
<PAGE>   8

     (c)  The Guarantor understands and acknowledges that if the Administrative
          Agent or any Lender forecloses judicially or nonjudicially against any
          real property security for the Obligations under the Loan Documents,
          that foreclosure could impair or destroy any ability that the
          Guarantor may have to seek reimbursement, contribution or
          indemnification from the Borrower, or MDDC, or others based on any
          right the Guarantor may have of subrogation, reimbursement,
          contribution or indemnification for any amounts paid by the Guarantor
          under this Completion Guaranty. The Guarantor further understands and
          acknowledges that in the absence of this Section 8, such potential
          impairment or destruction of the Guarantor's rights, if any, may
          entitle the Guarantor to assert a defense to this Completion Guaranty.
          By executing this Completion Guaranty, the Guarantor freely,
          irrevocably and unconditionally: (i) waives and relinquishes that
          defense and agrees that the Guarantor will be fully liable under this
          Completion Guaranty even though the Administrative Agent or the
          Lenders may foreclose judicially or nonjudicially against any real
          property security for the Obligations under the Loan Documents; (ii)
          agrees that the Guarantor will not assert that defense in any action
          or proceeding which the Administrative Agent or the Lenders may
          commence to enforce this Completion Guaranty; and (iii) acknowledges
          and agrees that the Administrative Agent and the Lenders are relying
          on this waiver in making the Loans and issuing the Letters of Credit,
          and that this waiver is a material part of the consideration which
          they are receiving for making the Loans and issuing the Letters of
          Credit.

9.   Revival and Reinstatement. If the Lenders are required to pay, return or
     restore to the Guarantor any amounts previously paid with respect to the
     Guaranteed Obligations because of any Insolvency Proceeding of the
     Guarantor, any stop notice or any other reason, the Guaranteed Obligations
     shall be reinstated and revived and the rights of the Administrative Agent
     and the Lenders shall continue with regard to such amounts, as though they
     had never been paid. This provision shall survive any termination of this
     Completion Guaranty.

10.  Representations and Warranties. The Guarantor hereby represents and
     warrants unto the Administrative Agent and each Lender as follows:

     (a)  The execution, delivery and performance by the Guarantor of this
          Completion Guaranty are within the Guarantor's corporate powers, have
          been duly authorized by all necessary corporate action, and do not

          (i)  contravene the Guarantor's Organizational Documents;

          (ii) contravene any contractual restriction, law or governmental
               regulation or court decree or order binding on or affecting the
               Guarantor or any of its properties; or

          (iii) result in, or require the creation or imposition of, any Lien on
               any of the Guarantor's properties.

                                       8
<PAGE>   9

     (b)  No authorization or approval or other action by, and no notice to or
          filing with, any governmental authority or regulatory body or other
          Person is required for the due execution, delivery or performance by
          the Guarantor of this Completion Guaranty.

     (c)  This Completion Guaranty constitutes the legal, valid and binding
          obligations of the Guarantor enforceable in accordance with its terms
          except as enforceability may be subject applicable bankruptcy,
          insolvency, reorganization, moratorium or other similar laws now or
          hereafter in effect relating to creditors rights generally, and/or
          general principles of equity.

     (d)  By its execution hereof, the Guarantor hereby also represents and
          warrants that as of the date hereof:

          (i)    the representations and warranties set forth in Article VI of
                 the Existing Senior Facility (excluding, however, those
                 contained in Section 6.7) are true and correct in all material
                 respects with the same effect as if now made (unless stated to
                 relate solely to an early date, in which case such
                 representations and warranties were true and correct as of such
                 earlier date);

          (ii)   no labor controversy, litigation, action, arbitration or
                 governmental investigation or proceeding is pending or, to the
                 knowledge of the Guarantor, threatened against the Guarantor or
                 any of its Subsidiaries which if adversely determined may
                 reasonably be expected to have a Material Adverse Effect; and

          (iii)  no Default (as defined in the Existing Senior Facility) has
                 occurred and is continuing under the Existing Senior Facility.

11.  Affirmative Covenants. Subject to Section 3, until the Final Completion
     Date, the Guarantor agrees as follows:

     (a)  The Guarantor will furnish to the Administrative Agent copies of the
          following financial statements, reports, notices and information:

          (i)    as soon as available and in any event within 45 days after the
                 end of each of the first three Fiscal Quarters of each Fiscal
                 Year of the Guarantor, consolidated balance sheets of the
                 Guarantor and its Subsidiaries as of the end of such Fiscal
                 Quarter and consolidated statements of income and cash flow of
                 the Guarantor and its Subsidiaries for such Fiscal Quarter and
                 for the period commencing at the end of the previous Fiscal
                 Year and ending with the end of such Fiscal Quarter, certified
                 by the chief financial officer of the Guarantor;

          (ii)   as soon as available and in any event within 90 days after the
                 end of each Fiscal Year of the Guarantor, a copy of the annual
                 audit report for such Fiscal Year for the Guarantor and its
                 Subsidiaries, including therein

                                       9
<PAGE>   10
                 consolidated balance sheets of the Guarantor and its
                 Subsidiaries as of the end of such Fiscal Year and consolidated
                 statements of income and cash flow of the Guarantor and its
                 Subsidiaries for such Fiscal Year, in each case certified
                 (without any Impermissible Qualification, as such term is
                 defined in the Existing Senior Facility) in a manner acceptable
                 to the Administrative Agent by Deloitte & Touche or other
                 independent public accountants reasonably acceptable to the
                 Administrative Agent (as such term is defined in the Existing
                 Senior Facility);

          (iii)  promptly after request by the Administrative Agent or any
                 Lender, copies of any detailed audit reports, management
                 letters or recommendations submitted to the board of directors
                 (or the audit committee of the board of directors) of the
                 Guarantor by independent accountants in connection with the
                 accounts or books of the Guarantor or any of its Subsidiaries,
                 or any audit of any of them;

          (iv)   as soon as possible and in any event within five days after the
                 Guarantor obtains knowledge of the occurrence of any Default
                 under the Existing Senior Facility, a statement of an
                 Authorized Officer of the Guarantor setting forth details of
                 such Default and the action which the Guarantor has taken and
                 proposes to take with respect thereto;

          (v)    as soon as possible and in any event within five days after the
                 Guarantor obtains knowledge of the (x) occurrence of any
                 material adverse development with respect to any labor
                 controversy, litigation, action or proceeding described in
                 Section 6.7 of the Existing Senior Facility (including, without
                 limitation, the entry against the Guarantor or any of its
                 Subsidiaries of a judgment in excess of $1,000,000) or (y)
                 commencement of any material labor controversy, litigation,
                 action or proceeding of the type described in Section 6.7 of
                 the Existing Senior Facility, notice thereof and, as promptly
                 as possible, but in no event later than ten Business Days after
                 such event, copies of all documentation relating thereto;

          (vi)   promptly after the sending or filing thereof, copies of all
                 reports which the Guarantor sends to any of its security
                 holders and copies of all material filings that the Guarantor
                 makes with any regulatory commission having jurisdiction over
                 the Guarantor (except to the extent that such reports are
                 restricted from disclosure by the particular regulatory
                 agency), and all reports and registration statements which the
                 Guarantor or any of its Subsidiaries files with the Securities
                 and Exchange Commission or any national securities exchange;

          (vii)  promptly upon becoming aware of the institution of any steps by
                 the Guarantor or any other Person to terminate any Pension
                 Plan, or the failure to make a required contribution to any
                 Pension Plan if such failure is sufficient to give rise to a
                 Lien under section 302(f) of ERISA, or the taking of any action
                 with respect to a Pension Plan which is reasonably

                                       10
<PAGE>   11
                 likely to result in the requirement that the Guarantor furnish
                 a bond or other security to the PBGC or such Pension Plan, or
                 the occurrence of any event with respect to any Pension Plan
                 which is reasonably likely to result in the incurrence by the
                 Guarantor of any material liability, fine or penalty, or any
                 material increase in the contingent liability of the Guarantor
                 with respect to any post-retirement Welfare Plan benefit,
                 notice thereof and copies of all documentation relating
                 thereto; and

          (viii) such other information respecting the condition or operations,
                 financial or otherwise, of the Guarantor or any of its
                 Subsidiaries as any Lender or the Administrative Agent may from
                 time to time reasonably request.

     (b)  The Guarantor agrees that it will perform, comply with and be bound by
          all of its agreements, covenants and obligations contained in Article
          VII of the Existing Senior Facility (other than Section 7.1 thereof).

     (c)  The Guarantor agrees that it will maintain a minimum of $50,000,000 of
          unused and available commitments under its Existing Senior Facility
          that it can borrow in accordance with the terms thereof.

12.  Negative Covenants. Subject to Section 3, until the Final Completion Date,
     the Guarantor agrees that the Guarantor will perform, comply with and be
     bound by all of its agreements, covenants and obligations contained in
     Article VIII of the Existing Senior Facility.

13.  Payments. All payments to be made hereunder by the Guarantor shall be made
     in lawful money of the United States of America at the time of payment,
     shall be made in immediately available funds, and shall be made without
     setoff, deduction (whether for Taxes, excluding taxes imposed on or
     measured by net income or receipts, or otherwise) or counterclaim.

14.  Consequences of Specified Events. Subject to Section 3, if at any time
     prior to the Final Completion Date (each of the following, a "Specified
     Event"),

     (a)  The Guarantor shall fail to pay within three days of the date when due
          any payment required to be made under this Completion Guaranty.

     (b)  Any representation or warranty of the Guarantor made hereunder or in
          any other Loan Document or any other writing or certificate furnished
          by or on behalf of the Guarantor to the Administrative Agent of any
          Lender for the purposes of or in connection with the Completion
          Guaranty is or shall be incorrect when made in any material respect.

     (c)  The Guarantor shall default in the due performance and observance of
          any of its obligations under Section 11(a) and such default shall
          continue unremedied for a period of thirty days after notice thereof
          shall have been given to the Guarantor by the Administrative Agent;
          provided, however, that the cure or waiver of Event of Default under
          the Existing Senior Facility shall result in automatic cure of the
          corresponding Event of Default under this Section 14(c) without any
          action by any party hereto.

                                       11
<PAGE>   12

     (d)  The Guarantor shall default in the due performance and observance of
          any of its obligations under Section 11(b) or Section 12 and such
          default shall continue unremedied for the applicable cure period
          therefor; provided, however, that the cure or waiver of Event of
          Default under the Existing Senior Facility shall result in automatic
          cure of the corresponding Event of Default under this Section 14(d)
          without any action by any party hereto.

     (e)  The Guarantor shall default in the due performance and observance of
          its obligations under Section 11(c) and such default shall continue
          unremedied for a period of two Business Days.

     (f)  An Event of Default shall have occurred and be continuing under the
          Existing Senior Facility provided, however, that the cure or waiver of
          Event of Default under the Existing Senior Facility shall result in
          automatic cure of the corresponding Event of Default under this
          Section 14(f) without any action by any party hereto;

     Then, at the option of the Required Lenders, an Event of Default shall
     exist under this Completion Guaranty and the Lenders, without any further
     notice to the Guarantor or any other Person, shall be entitled to exercise
     all rights and remedies available hereunder, under the other Loan Documents
     and at law and equity; provided, however, the Required Lenders may, at
     their option, demand performance by the Guarantor of the Guaranteed
     Obligations without declaring an Event of Default under the other Loan
     Documents.

15.  Miscellaneous Provisions.

     (a)  This Completion Guaranty is a Loan Document executed pursuant to the
          Credit Agreement and shall (unless otherwise expressly indicated
          herein) be construed, administered and applied in accordance with the
          terms and provisions thereof.

     (b)  This Completion Guaranty shall be binding upon and shall inure to the
          benefit of the parties hereto and their respective successors and
          assigns; provided, however, that the Guarantor may not assign or
          transfer its obligations hereunder without the prior written consent
          of the Administrative Agent and all Lenders, which consent shall be
          determined in good faith in their sole discretion.

     (c)  The provisions of this Completion Guaranty may from time to time be
          amended, modified or waived, if such amendment, modification or waiver
          is in writing and consented to by the Guarantor and the Required
          Lenders (unless the other Loan Documents would require such amendment
          to be consented to by all Lenders).

                                       12
<PAGE>   13
     (d)  All notices and other communications provided to any party hereto
          under this Completion Guaranty shall be in writing and addressed,
          delivered or transmitted to such party at its address or facsimile
          number set forth below its signature hereto or set forth in the Lender
          Assignment Agreement or Term Lender Joinder Agreement or at such other
          address or facsimile number as may be designated by such party in a
          notice to the other parties. All such notices and communications shall
          be deemed to have been properly given if (i) hand delivered with
          receipt acknowledged by the recipient; (ii) if mailed, upon the fifth
          Business Day after the date on which it is deposited in registered or
          certified mail, postage prepaid, return receipt requested or (iii) if
          by Federal Express or other nationally-recognized express courier
          service with instructions to deliver on the following Business Day, on
          the next Business Day after delivery to such express courier service.
          Notices and other communications may also be properly given by
          facsimile but shall be deemed to be received upon automatic facsimile
          confirmation of receipt thereof by the intended recipient's machine
          with the original of such notice or communication to be given in the
          manner provided in the second sentence of this Section; provided,
          however, that the failure to deliver a copy in accordance with the
          second sentence of this Section shall not invalidate the effectiveness
          of such facsimile notice.

If to the Administrative Agent:     Canadian Imperial Bank of Commerce
                                    200 West Madison Street
                                    Suite 2600
                                    Chicago, Illinois
                                    Attn: Mr. John D. Palomo
                                    Telephone No.: (312) 855-3225
                                    Facsimile No.: (312) 855-3235

With a copy to:                     CIBC World Markets Corp.
                                    350 South Grand Avenue
                                    Suite 2600
                                    Los Angeles, California  90071
                                    Attn: Mr. Dean J. Decker
                                    Telephone No.: (213) 617-6245
                                    Facsimile No.: (213) 346-0157

If to the Guarantor                 Boyd Gaming Corporation
                                    2950 South Industrial Road
                                    Las Vegas, Nevada 89109
                                    Attn: Chief Financial Officer
                                    Telephone No.: (702) 792-7210
                                    Facsimile No.: (702) 792-7313

with a copy to:                     Boyd Gaming Corporation
                                    2950 South Industrial Road
                                    Las Vegas, Nevada 89109
                                    Attn: General Counsel
                                    Telephone No.: (702) 792-7200
                                    Facsimile No.: (702) 792-7313

                                       13
<PAGE>   14

     (e)  No failure or delay on the part of the Administrative Agent or any
          Lender in exercising any power or right under this Completion Guaranty
          shall operate as a waiver thereof, nor shall any single or partial
          exercise of any such power or right preclude any other or further
          exercise thereof or the exercise of any other power or right. No
          notice to or demand on the Guarantor in any case shall entitle it to
          any notice or demand in similar or other circumstances. No waiver or
          approval by the Administrative Agent or any Lender under this
          Completion Guaranty shall, except as may be otherwise stated in such
          waiver or approval, be applicable to subsequent transactions. No
          waiver or approval hereunder shall require any similar or dissimilar
          waiver or approval thereafter to be granted hereunder.

     (f)  The various headings of this Completion Guaranty are inserted for
          convenience only and shall not affect the meaning or interpretation of
          this Completion Guaranty or any provisions hereof.

     (g)  Any provision of this Completion Guaranty which is prohibited or
          unenforceable in any jurisdiction shall, as to such provision and such
          jurisdiction, be ineffective to the extent of such prohibition or
          unenforceability without invalidating the remaining provisions of this
          Completion Guaranty or affecting the validity or enforceability of
          such provision in any other jurisdiction.

     (h)  THIS COMPLETION GUARANTY SHALL BE DEEMED TO BE A CONTRACT MADE UNDER
          AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW YORK (INCLUDING
          FOR SUCH PURPOSE SECTIONS 5-1401 AND 5-1402 OF THE GENERAL OBLIGATIONS
          LAW OF THE STATE OF NEW YORK). THIS COMPLETION GUARANTY AND THE OTHER
          LOAN DOCUMENTS CONSTITUTE THE ENTIRE UNDERSTANDING AMONG THE PARTIES
          HERETO AND THERETO WITH RESPECT TO THE SUBJECT MATTER HEREOF AND
          THEREOF AND SUPERSEDE ANY AND ALL PRIOR AGREEMENTS, WRITTEN OR ORAL,
          WITH RESPECT THERETO.

     (i)  ANY LITIGATION BASED HEREON, OR ARISING OUT OF, UNDER, OR IN
          CONNECTION WITH, THIS COMPLETION GUARANTY, OR ANY COURSE OF CONDUCT,
          COURSE OF DEALING, STATEMENTS (WHETHER ORAL OR WRITTEN) OR ACTIONS OF
          THE ADMINISTRATIVE AGENT, THE LENDERS, THE ISSUER OR THE GUARANTOR IN
          CONNECTION HEREWITH SHALL BE BROUGHT AND MAINTAINED EXCLUSIVELY IN THE
          COURTS OF THE STATE OF NEW YORK, IN NEW YORK COUNTY OR IN THE UNITED
          STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT OF NEW YORK; PROVIDED,
          HOWEVER, THAT ANY SUIT SEEKING ENFORCEMENT AGAINST ANY COLLATERAL OR
          OTHER PROPERTY MAY BE BROUGHT, AT THE ADMINISTRATIVE AGENT'S OPTION,
          IN THE COURTS OF ANY JURISDICTION WHERE SUCH COLLATERAL OR OTHER
          PROPERTY MAY BE FOUND. THE GUARANTOR HEREBY EXPRESSLY AND IRREVOCABLY
          SUBMITS TO THE PERSONAL JURISDICTION OF THE COURTS OF THE STATE

                                       14
<PAGE>   15

          OF NEW YORK AND OF THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN
          DISTRICT OF NEW YORK FOR THE PURPOSE OF ANY SUCH LITIGATION AS SET
          FORTH ABOVE AND IRREVOCABLY AGREES TO BE BOUND BY ANY JUDGMENT
          RENDERED THEREBY IN CONNECTION WITH SUCH LITIGATION. THE GUARANTOR
          HEREBY IRREVOCABLY APPOINTS CT CORPORATION SYSTEM (THE "PROCESS
          AGENT"), WITH AN OFFICE ON THE DATE HEREOF AT 1633 BROADWAY, NEW YORK,
          NEW YORK 10019, UNITED STATES, AS ITS AGENT TO RECEIVE, ON THE
          GUARANTOR'S BEHALF AND ON BEHALF OF THE GUARANTOR'S PROPERTY, SERVICE
          OF COPIES OF THE SUMMONS AND COMPLAINT AND ANY OTHER PROCESS WHICH MAY
          BE SERVED IN ANY SUCH ACTION OR PROCEEDING. SUCH SERVICE MAY BE MADE
          BY MAILING OR DELIVERING A COPY OF SUCH PROCESS TO THE GUARANTOR IN
          CARE OF THE PROCESS AGENT AT THE PROCESS AGENT'S ABOVE ADDRESS, AND
          THE GUARANTOR HEREBY IRREVOCABLY AUTHORIZES AND DIRECTS THE PROCESS
          AGENT TO ACCEPT SUCH SERVICE ON ITS BEHALF. AS AN ALTERNATIVE METHOD
          OF SERVICE, THE GUARANTOR FURTHER IRREVOCABLY CONSENTS TO THE SERVICE
          OF PROCESS BY REGISTERED MAIL, POSTAGE PREPAID, OR BY PERSONAL SERVICE
          WITHIN OR WITHOUT THE STATE OF NEW YORK AT THE ADDRESS FOR NOTICES
          SPECIFIED IN SECTION 15(D). THE GUARANTOR HEREBY EXPRESSLY AND
          IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY LAW, ANY
          OBJECTION WHICH IT MAY HAVE OR HEREAFTER MAY HAVE TO THE LAYING OF
          VENUE OF ANY SUCH LITIGATION BROUGHT IN ANY SUCH COURT REFERRED TO
          ABOVE AND ANY CLAIM THAT ANY SUCH LITIGATION HAS BEEN BROUGHT IN AN
          INCONVENIENT FORUM. TO THE EXTENT THAT THE GUARANTOR HAS OR HEREAFTER
          MAY ACQUIRE ANY IMMUNITY FROM JURISDICTION OF ANY COURT OR FROM ANY
          LEGAL PROCESS (WHETHER THROUGH SERVICE OR NOTICE, ATTACHMENT PRIOR TO
          JUDGMENT, ATTACHMENT IN AID OF EXECUTION OR OTHERWISE) WITH RESPECT TO
          ITSELF OR ITS PROPERTY, THE GUARANTOR HEREBY IRREVOCABLY WAIVES TO THE
          FULLEST EXTENT PERMITTED BY LAW SUCH IMMUNITY IN RESPECT OF ITS
          OBLIGATIONS UNDER THIS COMPLETION GUARANTY.

     (j)  BY THEIR ACCEPTANCE OF THIS COMPLETION GUARANTY THE ADMINISTRATIVE
          AGENT, THE LENDERS, THE ISSUER AND THE GUARANTOR HEREBY KNOWINGLY,
          VOLUNTARILY AND INTENTIONALLY WAIVE TO THE FULLEST EXTENT PERMITTED BY
          LAW ANY RIGHTS THEY MAY HAVE TO A TRIAL BY JURY IN RESPECT OF ANY
          LITIGATION BASED HEREON, OR ARISING OUT OF, UNDER, OR IN CONNECTION
          WITH, THIS COMPLETION GUARANTY OR ANY OTHER LOAN DOCUMENT, OR ANY
          COURSE OF CONDUCT, COURSE OF DEALING, STATEMENTS (WHETHER ORAL OR
          WRITTEN) OR ACTIONS OF THE ADMINISTRATIVE AGENT, THE LENDERS, THE
          ISSUER OR THE GUARANTOR IN CONNECTION HEREWITH OR THEREWITH. THE
          GUARANTOR ACKNOWLEDGES AND AGREES THAT IT HAS RECEIVED FULL AND
          SUFFICIENT CONSIDERATION FOR THIS PROVISION (AND EACH OTHER PROVISION
          OF EACH OTHER LOAN DOCUMENT TO WHICH IT IS A PARTY) AND THAT THIS
          PROVISION IS A MATERIAL INDUCEMENT FOR THE ADMINISTRATIVE AGENT AND
          THE LENDERS ENTERING INTO EACH LOAN DOCUMENT TO WHICH SUCH PERSON IS A
          PARTY.

                                       15

<PAGE>   16

     IN WITNESS WHEREOF, the Guarantor has caused this Completion Guaranty to be
duly executed and delivered by its officers thereunto duly authorized as of the
date first above written.

                                              BOYD GAMING CORPORATION,
                                              a Nevada corporation

                                              By:
                                                 -------------------------------
                                                 Title: Executive Vice President

                                       16

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