<PAGE>   1
                                                                   Exhibit 10.28



                      FIRST AMENDMENT TO CREDIT AGREEMENT


       THIS FIRST AMENDMENT TO CREDIT AGREEMENT (herein called this "Amendment")
is made as of March 27, 2001 by and between North Coast Energy, Inc., a Delaware
corporation ("Borrower"), and Union Bank of California, N.A., as Agent (herein
called "Agent"), and the other Lenders from time to time parties to the Credit
Agreement (as defined below).

                              W I T N E S S E T H:

       WHEREAS, Borrower, Agent and Lenders have entered into that certain
Credit Agreement dated as of September 26, 2000 (as amended, supplemented, or
restated to the date hereof, the "Original Agreement"), for the purposes and
consideration therein expressed, pursuant to which Lenders became obligated to
make loans to Borrower as therein provided; and

       WHEREAS, Borrower, Agent, and Lenders desire to amend the Original
Agreement as provided herein.

       NOW, THEREFORE, in consideration of the premises and the mutual covenants
and agreements contained herein and in the Original Agreement, in consideration
of the loans which may hereafter be made by Lenders to Borrower, and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto do hereby agree as follows:

                                   ARTICLE I.

                           DEFINITIONS AND REFERENCES

       Section 1.1  TERMS DEFINED IN THE ORIGINAL AGREEMENT. Unless the context
otherwise requires or unless otherwise expressly defined herein, the terms
defined in the Original Agreement shall have the same meanings whenever used in
this Amendment.

       Section 1.2.  OTHER DEFINED TERMS. Unless the context otherwise requires,
the following terms when used in this Amendment shall have the meanings assigned
to them in this Section 1.2.

                     "AMENDMENT" means this First Amendment to Credit Agreement.

                     "CREDIT AGREEMENT" means the Original Agreement as amended
              hereby.

                                  ARTICLE II.

                        AMENDMENT TO ORIGINAL AGREEMENT

       Section 2.1.  HEDGING CONTRACTS. Each reference to "seventy-five percent
(75%)" in Section 7.3(a) of the Original Agreement is hereby amended to read
"eighty-five percent (85%)".

<PAGE>   2

                                  ARTICLE III.

                          CONDITIONS OF EFFECTIVENESS

       Section 3.1. CONDITIONS OF EFFECTIVENESS. This Amendment shall become
effective as of the date first above written when and only when each of the
following conditions shall have been satisfied:

              (a) Agent shall have received, at Agent's office, each of the
       following in form, substance and date satisfactory to Agent: (i) a
       counterpart of this Amendment executed and delivered by Borrower and
       Majority Lenders; and (ii) a certificate of a duly authorized officer of
       Borrower dated the date of this Amendment certifying: (A) that all of the
       representations and warranties set forth in Section 4.1 hereof are true
       and correct at and as of the time of such effectiveness; and (B) as to
       such other corporate matters as Agent shall deem necessary; and

              (b) Agent shall have additionally received such other documents as
       Agent may reasonably request.

                                  ARTICLE IV.

                         REPRESENTATIONS AND WARRANTIES

       Section 4.1. REPRESENTATIONS AND WARRANTIES OF BORROWER. In order to
induce Agent and Lenders to enter into this Amendment, Borrower represents and
warrants as of the date on which this Amendment becomes effective to Agent that:

              (a) The representations and warranties contained in Article V of
       the Credit Agreement are true and correct at and as of the time of the
       effectiveness hereof.

              (b) Each Restricted Person is duly authorized to execute and
       deliver each Loan Document to which it is a party and Borrower is and
       will continue to be duly authorized to borrow and to perform its
       obligations under the Credit Agreement. Each Restricted Person has duly
       taken all corporate action necessary to authorize the execution and
       delivery of each Loan Document to which it is a party and to authorize
       the performance of the obligations of it hereunder and thereunder.

              (c) The execution and delivery by each Restricted Person of the
       Loan Documents to which it is a party, the performance by each Restricted
       Person of its obligations hereunder and thereunder, and the consummation
       of the transactions contemplated hereby and thereby do not and will not
       conflict with any provision of law, statute, rule or regulation or of the
       articles of incorporation and bylaws of any Restricted Person, or of any
       material agreement, judgment, license, order or permit applicable to or
       binding upon any Restricted Person, or result in the creation of any
       lien, charge or encumbrance upon any assets or properties of any
       Restricted Person. Except for those


                                      -2-
<PAGE>   3


       which have been duly obtained, no consent, approval, authorization or
       order of any court or governmental authority or third party is required
       in connection with the execution and delivery by any Restricted Person of
       the Loan Documents to which it is a party, or to consummate the
       transactions contemplated hereby and thereby.

              (d) When duly executed and delivered, each of this Amendment and
       each Loan Document (as amended or affected by this Amendment) will be a
       legal and binding instrument and agreement of each Restricted Person that
       is a party thereto, enforceable in accordance with its terms, except as
       limited by bankruptcy, insolvency and similar laws applying to creditors'
       rights generally and by principles of equity applying to creditors'
       rights generally.

              (e) The audited quarterly financial statements of Borrower dated
       as of December 31, 2000 fairly present the financial position at such
       dates and the statement of operations and the changes in financial
       position for the periods ending on such dates for Borrower. Copies of
       such financial statements have heretofore been delivered to Agent. Since
       December 31, 2000, no material adverse change has occurred in the
       financial condition or businesses of Borrower.

                                   ARTICLE V.

                                 MISCELLANEOUS

       Section 5.1.  RATIFICATION OF AGREEMENTS. Each Loan Document, as amended
or affected hereby, is hereby ratified and confirmed in all respects. Any
reference to the Credit Agreement in any Loan Document shall be deemed to refer
to this Agreement also. The execution, delivery and effectiveness of this
Amendment shall not, except as expressly provided herein or therein, operate as
a wavier of any right, power or remedy of Agent or Lenders under the Credit
Agreement or any other Loan Document nor constitute a waiver of any provision of
the Credit Agreement or any other Loan Document.

       Section 5.2.  SURVIVAL OF AGREEMENTS. All representations, warranties,
covenants and agreements of Borrower herein shall survive the execution and
delivery of this Amendment and the performance hereof, including without
limitation the making or granting of the Loan, and shall further survive until
all of the Obligations are paid in full. All statements and agreements contained
in any certificate or instrument delivered by any Restricted Person hereunder or
under the Credit Agreement to Agent shall be deemed to constitute
representations and warranties by, or agreements and covenants of, Borrower
under this Amendment and under the Credit Agreement.

       Section 5.3.  LOAN DOCUMENTS. This Amendment is a Loan Document, and all
provisions in the Credit Agreement pertaining to Loan Documents apply hereto and
thereto.


                                      -3-
<PAGE>   4


       Section 5.4.  GOVERNING LAW. This Amendment shall be governed by and
construed in accordance with the laws of the State of Texas and any applicable
laws of the United States of America in all respects. including construction,
validity and performance.

       Section 5.5. COUNTERPARTS. This Amendment may be separately executed in
counterparts and by the different parties hereto in separate counterparts, each
of which when so executed shall be deemed to constitute one and the same
Amendment.

       THIS AMENDMENT AND THE OTHER LOAN DOCUMENTS REPRESENT THE FINAL
AGREEMENET BETWEEN THE PARTIES AND MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR,
CONTEMPORANEOUS, OR SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO
UNWRITTEN ORAL AGREEMENTS OF THE PARTIES.



                                      -4-
<PAGE>   5


       IN WITNESS WHEREOF, this Amendment is executed as of the date first above
written.

                                        NORTH COAST ENERGY, INC.


                                        By: /s/ Omer Yonel
                                           -------------------------------------
                                           Omer Yonel
                                           Chief Executive Officer


                                        UNION BANK OF CALIFORNIA, N.A., as
                                        Agent and Lender


                                        By: /s/ Randall L. Osterberg
                                           -------------------------------------
                                           Name: Randall L. Osterberg
                                           Title: Senior Vice - President


                                        BANK ONE, NA (Main Office Chicago),
                                        Lender


                                        By: /s/ Charles Kingswell-Smith
                                           -------------------------------------
                                           Name:  Charles Kingswell-Smith
                                           Title: First Vice President


                                        COMERICA BANK-TEXAS, Lender


                                        By: /s/ H. Vadgama
                                           -------------------------------------
                                           Name:   Huma Vadgama
                                           Title:  Corporate Banking Officer


                                        FORTIS CAPITAL CORP., Lender


                                        By: /s/ Deirdre Sanborn
                                           -------------------------------------
                                           Name:   Deirdre Sanborn
                                           Title:  Vice President



                                        By: /s/ John C. Preneta
                                           -------------------------------------
                                           Name:   John C. Preneta
                                           Title:  Executive Vice President




                                      -5-