• Sonic Casino Night Music
• Sonic 3 Casino Night Act 2020

• Sonic The Hedgehog 2. Emerald Hill Zone: Act 1 / Act 2; Chemical Plant Zone: Act 1 / Act 2; Aquatic Ruin Zone: Act 1 / Act 2; Casino Night Zone: Act 1 / Act 2; Hill Top Zone: Act 1 / Act 2; Mystic Cave Zone: Act 1 / Act 2; Oil Ocean Zone: Act 1 / Act 2; Metropolis Zone: Act 1 / Act 2 / Act 3; Sky Chase Zone: no map. It's not like there IS.
• This is where I'll be putting my remixes for Sonic 2 Expanded! Emerald Hill Act 2 Chemical Plant Act 2 Aquatic Ruin Act 2 Wood Act 1 Wood Act 2 Casino Night Act 2 Hill Top Act 2 Golden Garden Act 1 Golden Garden Act 2 Mystic Cave Act 2 Hidden Palace Act 1 Jade Temple Act 1 Jade Temple Act 2 Oil Ocean Act 2.

S3AIR +7 ↺1 Sonic 3 A.I.R. Brawlhalla +3 ↺4 MK8 +6 Mario Kart 8; Celeste +3 ↺2. This is a mod that replaces Studiopolis Zone with a recreation of Casino Night Zone. Currently only act 1 is finished but i already have some of act 2 finished, and it will be completely finished soon.

This is a sub-page of Proto:Sonic the Hedgehog 2 (Genesis).

The Simon Wai prototype of Sonic the Hedgehog 2 is definitely further along than the Nick Arcade build, but there are still quite a few unfinished elements such as level layouts and things that have not been fully implemented. There are also many, many unused graphics that can be found via hacking. In addition, there are a few levels not seen in the final, but most of them contain nothing. The Simon Wai prototype is known as one of the first video game prototypes to be dissected in detail. It kickstarted interest in prototypes for not only the Sonic fanbase, but also the gaming community at large.

According to drx, this prototype was built in early August 1992. The prototype is named after Simon Wai, who found it on a Chinese Geocities page in 1998. However, it is believed to have first been leaked in September 1992 and distributed through BBS (bulletin board system) numbers. The origin of the actual ROM image is unknown. Magazines from the time attributed the leak to a specific magazine, while Yuji Naka stated in 2005 that it came from a demonstration cart that was stolen from a New York toy fair in 1992, then dumped.

• 1General Notes
• 2Zones
• 4Unused Graphics and Objects
• 7Early Zone Leftovers

General Notes

• The SEGA logo does not appear when booting up the game. However, if you get a Game Over or clear the four zones, the game does show the SEGA logo and then shows the title screen. This also happens if you stay on the title screen and allow the resulting demo to run its course. The sound is also noticeably higher pitched than in the final.
• Uses the earlier title screen and lacks the title menu.
• Any zone with water will be glitched when playing in two-player mode, as the game loads the graphics incorrectly.
• Special Stages are still not present, although the music is.
• Debug's info is now properly white in every zone.
• The lower-right four digits now reserve the water level height (even in zones without water), while the lower-left four digits count up by one, every in-game second.
• Entering and exiting debug now automatically brings Tails to the player's location.
• Locking on this prototype with Sonic & Knuckles will unlock the full Blue Sphere game, as it does with the Nick Arcade build. This is because the two prototypes have the same serial code as Sonic the Hedgehog (REV01), which determines the result of the lock-on.
• Rolling demo gameplay is the same as the Nick Arcade build, and has not yet been rerecorded to fit subsequent layout changes.
• The level select has the same general appearance as the level select from Sonic 1.
• Special Stage cannot be selected on the level select, as they don't exist yet.
• There are no checkpoints in the game. One can be placed via Debug Mode, where it can be seen that they have a totally different design to the one used in the final game.
• The player starts most Acts positioned slightly more to the left than they do in the final game. However, this doesn't affect all levels.

Cheat Codes

• Level Select - A + Start.
• 'Night Mode' - C + Start.
  • Unlike the final game, Debug mode doesn't need to be active for this to work.
• Two-Player Mode - on the level select, press B + Start on any level that doesn't have water.
• Debug Mode - C, C, Up, Down, Down, Down, Down, Up.
  • You can also enable it through the patch code FFFFFA:0001. The ring sound will play even if C is never pressed, but nothing else happens.
  • Layer switches are visible in this version's Debug Mode. A checkpoint sound is made whenever Sonic or Tails passes through them.
  • Tails jumps to Sonic's position when leaving Object Placement mode.

Gameplay

• At this point, Tails is still quasi-independent:
  • Player 2 is able to control Tails, except Tails will also follow Sonic.
  • Tails cannot complete a level on his own, since the game only loads the goal sign when Sonic approaches it.
  • The AI is much simpler; it only follows Sonic and does not try to keep up.
  • Tails loses the player's rings when he is hit.
  • If he dies, he drops back in from the top of the screen and immediately goes into a roll when he hits the ground because he can't fly yet.
• If Player 1 completes a level, Tails can be controlled if Sonic is off-screen.
• As with the Nick Arcade build, the spin dash is still a work-in-progress, as Sonic and Tails can only charge it up once; the sound for when Sonic spins in Sonic the Hedgehog is still heard due to there not yet being a specific sound effect for the spin dash.
• As with the Nick Arcade build, the timer resets to 9:00 when it approaches 9:59 in order to allow the player to test the stages for extended periods of time.
• The screen doesn't scroll up or down when you look up or down for a certain period of time.
• Bubbles are loaded incorrectly from the VRAM.
• A unique bug is present in this prototype: upon collecting 100 rings, the game will play the Death Egg Zone music instead of the usual 1-Up sound. This is because sound bank 88 (which was the 1-Up sound in the Nick Arcade build) has since been overwritten and not edited to play the correct sound. Game Genie code XCOT-AAC4 will cause the correct tune to play. The monitors, on the other hand, were programmed with the correct 1-Up sound.
• The underwater countdown music uses the Level Select theme. When Sonic gets out of the water, the Emerald Hill music begins.
• Spike behavior is the same as in Sonic 1 - getting hit does not give the player invincibility frames to avoid being immediately hurt from other spikes.
• Rolling tubes do not force the player to roll, notably in Hill Top and Hidden Palace.
• Speed Shoes do not increase the speed of the music.
• No title cards or score tallies appear at the beginning and end of an Act respectively. However, the clear theme does play in the case of the latter.
• The splashing animation is corrupted, showing misaligned bubbles instead of a splashing sprite. Tails has no splashing effects.
• 2-Player mode has the split-screen for Sonic and Tails, but is otherwise identical to 1-Player mode. The level will still restart if Sonic dies.
• Aquatic Ruin, Chemical Plant, Hill Top, and Emerald Hill are the only Zones where signposts appear. Capsules do not exist yet.

Zones

Without accessing the level select, the game allows you to play Aquatic Ruin, Chemical Plant, Hill Top, and Emerald Hill. After beating the Emerald Hill boss, the game resets to the Sonic 1 SEGA screen despite being disabled from appearing at startup.

Internal Zone Order

Zones that are either placeholders or leftover from a previous build are in italics, new levels are bold, and moved level slots are blue.

This earlier Zone order seems to largely match the order seen in early concepts for the game which involved time travel. Zone 01 would be Ocean Wind, Zone 03 would be Sand Shower, Zone 06 would be Blue Lake, and Zone 09 would be Rock World. However, there are some deviations from those concepts even at this point in development: it appears that Zone 05 was likely going to be Tropical Plant, and it's Metropolis 3 both here and in the final. Additionally, Neo Green Hill doesn't appear in any of those timezone maps. Most curiously, Mystic Cave is also unmentioned in those concepts, and is called Dust Hill here; the latter name is mentioned in the early timeline and assigned to what seems to be a crumbling Green Hill.

For most Zones out of the 'normal' game loop (Neo Green Hill -> Chemical Plant -> Hill Top -> Green Hill), placing object 3A in the final Act will make the game jump to the next Zone by ID. For Ocean Wind, Sand Shower, Blue Lake, Rock World, and Death Egg, the game will jump to Green Hill.

Subpages

Sonic Casino Night Music

Ocean Wind Zone (ID 01)

• Uses Emerald Hill's palette and music, complete with a lack of debug mode objects aside from the ring and Static Monitor.

This empty stage slot can be accessed by entering Game Genie code AA7A-ACGY or Pro Action Replay code FFFE10:0100 and choosing Green Hill Zone Stage 0. As with Genocide City, Death Egg, and Wood Zone Act 2, Sonic and Tails immediately fall to their deaths upon entering.

Going by early concept art which shows roughly what the level order would have originally looked like, and lines up rather closely with the internal order, this slot was going to be used for a level called 'Ocean Wind Zone'.

Wood Zone (ID 02)

A scrapped Zone. It seems that only a small portion was ever implemented and did not get too far.

• What exists of the level quickly ends because of a ramp that has a solid platform blocking the top of it, which is impossible to get past without Debug Mode. Even then, the rest of the level is incomplete, with a nonfunctional conveyor belt near the top.
• Plays the music for Metropolis Zone.
• If you use Debug Mode, you can move upwards in the level and find a conveyor belt, but it doesn't work.
• Level collision is glitchy.
• Unlike any other zone in the game, the entire background is located under the stage instead of in the background layer.
• Act 2 is empty, containing nothing but Sonic and Tails falling to their deaths.

Sonic 3 Casino Night Act 2020

• Layout

Sand Shower Zone (ID 03)

• Uses the final Oil Ocean theme, and only has the default Ring and Static monitor objects in debug mode.

This empty stage slot can be accessed by entering Game Genie code AA7A-AGGY or Pro Action Replay code FFFE10:0300 and choosing 'Green Hill Zone Stage 0' on the stage select. Like Genocide City and Death Egg, this stage uses Emerald Hill's palette and is entirely empty, causing Sonic and Tails to immediately fall to their deaths upon entering. In the Nick Arcade prototype, this slot was used for Emerald Hill Zone.

Blue Lake Zone (ID 06)

• Contains a pitch-black background, uses what would become the two-player Emerald Hill Zone theme in the final, and only has default Ring and Static monitor objects in debug mode.

This is an empty stage slot that can be accessed by entering the Game Genie code AA7A-ANGY or Pro Action Replay code FFFE10:0600 and choosing 'Green Hill Stage 0' on the stage select. As with the others, the stage is entirely empty, prompting Sonic and Tails to fall to their immediate deaths upon entering.

According to concept art, which closely matches up with the internal stage order, this was originally meant for a stage called 'Blue Lake Zone'; from September 14th onwards, the stage is used for Wing Fortress Zone.

Hidden Palace Zone (ID 08)

Has very few changes from the previous version. For more information, see the Nick Arcade prototype page.

• This Zone has had mainly minor behind-the-scenes changes since the Nick Arcade build.
• Sonic and Tails have had their underwater palette updated.
• The music has been changed to what would be the 2P VS version of Mystic Cave in the final.
• The debug list has had a face lift, and all the unused objects that were in the Nick Arcade build are now gone. The items that are still there have fixed previews.
• The collision bug caused by spindashing into the big emerald from far away has been fixed.
• The art for Emerald Hill's enemies are no longer loaded in this Zone.
• This and Emerald Hill are the only Zones in this build with badniks in it.

Rock World Zone (ID 09)

• Uses the Emerald Hill Zone palette, the Sky Chase Zone theme as its default background music, and only has default Ring and Static monitor objects in debug mode.

By entering Game Genie code AA7A-AWGY or Pro Action Replay code FFFE10:0900 and choosing 'Green Hill Stage 0' on the stage select, the player will be taken to yet another empty Zone that promptly causes Sonic and Tails to fall to their deaths.

Genocide City Zone (ID 0E)

• Both Acts use Chemical Plant's music, Emerald Hill's palette, and the default Ring and Static Monitor objects in debug mode. They're also completely empty.

This Zone was originally designed as a single-Act mechanical-themed area. It is called 'Genocide City' in this build because of an average understanding of English by the person who originally named it, then changed to Cyber City after this prototype. Before the team started putting it in the game, though, it was scrapped; the level design was used for Metropolis Act 3, while the graphics were used in Level 3 of Sonic Spinball (The Machine).

Interestingly, the level slot for this level was overwritten with Death Egg in the final, while the slot for Death Egg in this prototype (ID 10) was overwritten with Sky Chase.

Death Egg Zone (ID 10)

• Both Acts use Emerald Hill's palette, but play no music and are empty. Dying here causes all sound to cut off. However, if you use the 100 ring glitch via debug mode and then die, it will not cut off for that particular death.

Music

The tracks for the final's invincibility, drowning, ending, Song #10, and credits themes are all nonexistent while the continue, game over, extra life, and Chaos Emerald fanfares are already in their final form. Everything else, however, is at least slightly different. Most, if not all, are based on the Masa's Demo versions of the tracks (notably Super Sonic and Casino Night Zone).

Unused Graphics and Objects

Most of the changed and unused graphics and objects in the Nick Arcade prototype are still here, with the following exceptions:

• The signposts and fireballs use their final graphics.
• The early animated Chemical Plant Zone graphics are no longer in the ROM.
• The JIS X 0201 character set has been deleted.
• Hill Top Zone's one-way barrier and the nebulous gray switch have been coded and placed in various Zones.
• The Chemical Plant Zone floating platforms now behave as they do in the final game.

Graphics

Objects

Monitor subtype 08. Breaking this monitor will load Super Sonic's palette.

The same effect can be seen through Pro Action Replay code FFF65F:FF00. Super Sonic's unique sprites, speed, invincibility, jump height, and ring drain are not yet present.

Unused Auto Demo

There's partial data for a Metropolis Zone Act 3 in the demo table that can be viewed using patch code FFFFF2:0004.

This is actually caused by the demo table not being converted after the Nick Arcade prototype:

02 is Chemical Plant, 03 is Hidden Palace, 04 is Green Hill, and 05 is Hill Top. The first four entries are valid, while the remaining entries are placeholders.

In the Simon Wai prototype, the table was changed:

Chemical Plant, Hidden Palace, Green Hill, and Hill Top use their new level IDs, but the duplicate Green Hill and Hill Top entries were not converted. They now point to Metropolis Act 3 and Metropolis Act 1/2 respectively.

The Metropolis Zone demo uses the input from the 2P Green Hill demo, which doesn't really work out.

Unassembled Data

Located at address 0xE5946 is a snippet of unassembled data. It starts with the comment at the top

...which translates to

What follows is a bunch of 'dc.b's for the actual chunk data. When assembled, its data matches the beginning of Neo Green Hill Zone's chunk data located at 0xBF568. While a good chunk of the unassembled data is there, it gets cut off.

Early Zone Leftovers

Starting at 0xC2148 in the ROM is leftover zone data from an earlier point in development.

Early Casino Night Chunks

Located at 0xC2148-0xC943C is what looks to be chunk data for a very early version of Casino Night zone. The beginning of the data is cut off, but when it is aligned, the shapes of the chunks line up with the chunk data that's normally used in the prototype. They appear to be very early, as none of the data that's used in the prototype matches the chunk mappings.

Early Chemical Plant Remnants

Starting at offset 0xC943C is data for an early version of Chemical Plant, which includes tiles, block and chunk data. They are much different from the used data, and when formatted correctly, line up much more with the layout from the Nick Arcade prototype.

Early Neo Green Hill Zone Remnants

Starting at 0xD602E is a bunch of early data related to Neo Green Hill Zone, including chunks, blocks, and 2 sets of tiles, with one set being cut off by some waterfall graphics.

Also located at 0x42374 - 0x4265F is an unused BG layout that is similar to the Act 2 layout used in the final game. Overall, the zone appears to have not changed much between these two versions.

Chiki Chiki Boys Data Leftovers

Several remnants exist in various parts of the ROM, though here they're little more than padding. The locations of the data in the Sonic 2 ROM match the equivalent area in both versions of the Chiki Chiki Boys ROM, but with some slight differences suggesting that the remnants here may be from a prototype.

Miscellaneous data can be found at:

• 0x24A30-0x27FFF
• 0x437BC-0x43FFF
• 0x46350-0x47FFF
• 0x48DB4-0x4FFFF