Sonic the Hedgehog 2 (Aug 21, 1992 prototype)

A prototype of Sonic the Hedgehog 2 for the Sega Mega Drive.
==Notes==
* Like the Simon Wai build, the game does not boot up to the Sega logo. However, the Sega logo will display after a level demo. The Sega logo is the same as the one from Sonic 1.
* Hidden Palace Zone, Wood Zone, Genocide City Zone, Death Egg Zone, and the Special Stage are present in the same state as they were in the Simon Wai prototype.
* None of the unused zone IDs contain any data aside from an associated music ID.
* Different title screen in comparison to the final.
* Cheat Codes:
** Level Select - A + Start.
** "Night Mode" - C + Start.
** Two-Player Mode - on the level select, press B + Start.
** Debug Mode - on the title screen, press C, C, Up, Down, Down, Down, Down, Up. Then hold A while selecting a level from the level select.
* The timer will still reset from 9:59 to 9:00 like in the earlier builds.
* The same left over data that was present in Simon Wai also exists in this build in the same area of the ROM.
* This build is similar in ways to the Simon Wai prototype. In comparison to that build, this prototype contains the following differences:
** Sonic’s final sprite has been implemented.
** Super Sonic has been implemented.
** The level order in this prototype is: Green Hill (Emerald Hill), Chemical Plant, Metropolis, Hill Top, Dust Hill (Mystic Cave), and Neo Green Hill (Aquatic Ruin). The prototype ends after completing Aquatic Ruin.
** The cut badnik in Green Hill Zone has been removed. It isn’t present in the object list for this stage, but the code and art still exists. For some reason, the object ID changed from $54 to $59.
** The Spiny badnik is blue instead of red in this build.
** Green Hill Zone’s boss plays Chemical Plant Zone’s theme instead.
** The cut elevator platform used in the Simon Wai prototype in Metropolis has been removed but is still present in the object list for this stage.
** The Hill Top Zone boss has been implemented. The boss arena is slightly different, the boss lacks any sound effects, and doesn’t start the boss music when encountered. The horizontal screen lock isn’t used to lock the player to the arena, so the player can walk away from the boss at any time.
** Dust Hill Zone now has additional objects to make the zone playable.
** The boss for Dust Hill Zone has been implemented. The screen lock hasn’t been set for the boss arena completely yet. The boss spawns above the intended area, so it often moves in midair. The falling stalagmites are missing, only the rocks seem to appear.
** Casino Night Zone is more complete in this prototype. The level layout itself isn’t broken, but is still devoid of objects except for one in Act 2. The only level specific object that appears in the object list for the stage is a single bumper. However, the art queue for the stage loads art for additional objects not included in the object list. The boss has been implemented and appears at the end of Act 2 but appears to be a work in progress. One major difference is that the spiked ball that Robotnik drops bounces around whereas it’s stationary in the final. Robotnik also seems to have a fixed movement pattern.
** The level layout in Oil Ocean Zone doesn’t seem to match the object layout, as there are switches and other objects suspended in midair all throughout the level.
** For the most part, the music tracks have all been finalized in this build. The game seems to be using a similar sound driver in comparison to the Simon Wai build.
** The unused BGM track from the final version has been implemented.
** The invincibility theme contains a different ending.
** The title screen theme is slightly different.
** The staff credits theme hasn’t been implemented. Instead, the unused BGM track is repeated in its place.
** Additional, unused sound effects have been added since the Simon Wai build.
** The art for the Sky Chase/Wing Fortress badniks exists in this build but aren't referenced by any art queue list. There doesn't seem to be zone art for these zones yet, however.
** No art for Death Egg Zone (Silver Sonic, etc) seems to exist yet.
** Entries to load the art for various cut badniks are located within Hidden Palace Zone's art queue list for some reason. Most of the art loads at $8000 in VRAM, overwriting the region each time a new archive is uncompressed.
** The code and art for the unused bosses actually exist in this build. This build even includes references to load the boss art for each zone with an art queue list, but goes unused.
** The routines responsible for loading the Metropolis boss in Act 3 exists in the game. However, the object itself is set to move around at coordinates that fit the end of Act 2 instead.
** There is an unused badnik/object that is unique to this build at object ID $5a. The object has a unique spawn animation and changes its sprite depending on where Sonic is around the object. Defeating the badnik leaves some art behind that remains stationary. This is an early version of the "Crawler" badnik that comes out of the ground. The mappings for the object seem to manipulate $7880 in VRAM.
==Screenshots==
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.34.00.png|Title screen.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.34.04.png|Level select.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.34.26.png|Green Hill Zone.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.35.20.png|Green Hill Zone Boss.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.35.38.png|Wood Zone.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.35.54.png|Metropolis Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.36.15.png|Metropolis Zone Act 2.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.36.31.png|Metropolis Zone Act 3.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.36.46.png|Hill Top Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.37.25.png|Hill Top Zone Boss.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.37.55.png|Hidden Palace Zone.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.38.43.png|Oil Ocean Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.39.00.png|Oil Ocean Zone Act 2.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.39.41.png|Dust Hill Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.40.15.png|Dust Hill Zone Boss.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.40.43.png|Casino Night Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.41.23.png|Casino Night Zone Boss.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.41.57.png|Chemical Plant Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.42.32.png|Chemical Plant Zone Act 2.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.42.55.png|Neo Green Hill Zone Act 1.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.43.20.png|Neo Green Hill Zone Act 2.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.43.32.png|Genocide City Zone.
Sonic the Hedgehog 2 (Aug 21, 1992 prototype).2019-09-13 20.43.42.png|Death Egg Zone.
==Videos==
<youtube width="320" height="224">55u4qr0hSEM</youtube>
==Files==
File Archive Contents
==Header==
00000100 53 45 47 41 20 4d 45 47 41 20 44 52 49 56 45 20 SEGA MEGA DRIVE 
00000110 28 43 29 53 45 47 41 20 31 39 39 31 2e 41 50 52 (C)SEGA 1991.APR
00000120 53 4f 4e 49 43 20 54 48 45 20 20 20 20 20 20 20 SONIC THE 
00000130 20 20 20 20 20 20 48 45 44 47 45 48 4f 47 20 32 HEDGEHOG 2
00000140 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 
00000150 53 4f 4e 49 43 20 54 48 45 20 20 20 20 20 20 20 SONIC THE 
00000160 20 20 20 20 20 20 48 45 44 47 45 48 4f 47 20 32 HEDGEHOG 2
00000170 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 
00000180 47 4d 20 30 30 30 30 34 30 34 39 2d 30 31 af c7 GM 00004049-01..
00000190 4a 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 J 
000001a0 00 00 00 00 00 07 ff ff 00 ff 00 00 00 ff ff ff ................
000001b0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 
000001c0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 
000001d0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 
000001e0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 
000001f0 4a 55 45 20 20 20 20 20 20 20 20 20 20 20 20 20 JUE 
==Origin==
Sonic the Hedgehog 2 (Aug 21, 1992 prototype) - EPROMs.jpeg|EPROMs.
== See also ==
* The Cutting Room Floor