Sonic the Hedgehog 2 (Simon Wai prototype)

From Sonic Retro


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Sonic the Hedgehog 2
Publisher: Sega
System(s): Sega Mega Drive
ROM size: 1 MB
Genre: Action

The Sonic the Hedgehog 2 "Simon Wai" prototype is a prototype build of Sonic the Hedgehog 2 for the Sega Mega Drive. It is a relatively early build of the game, thought to have been created around the middle of 1992.

This particular prototype is named after Simon Wai, who found the ROM on a Chinese website and subsequently brought it to the attention of the Western Sonic the Hedgehog fan community. It was the first prototype to be found of Sonic 2, and for many years was simply referred to as "Sonic 2 Beta".

The Simon Wai prototype is more advanced than the earlier "Nick Arcade" prototype, though is still very much incomplete. Only four levels can be played during normal gameplay; Aquatic Ruin Zone, Chemical Plant Zone, Hill Top Zone and Emerald Hill Zone (in that order). A further nine can be accessed through a level select code, though none of these levels can be finished, and three are entirely empty stages.

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Various Differences


  • Instead of playing the 1-Up sound when Sonic gets 100 or 200 rings, the game plays a prototype version of the music from Death Egg Zone (Death Egg Zone plays no music). However, if Sonic breaks open a 1-Up monitor, the proper 1-Up sound will play. The reason why this happens is because sound bank $88, which was the 1-Up sound in the Nick Arcade prototype, is now the Death Egg theme and wasn't overwritten.
  • Tails has no balancing sprites, instead he uses a tail-less slowly animated version of his waiting sprites.
  • The concept for a partner is still a work in progress as Tails can lose rings for the player when hit, just like in the Nick Arcade prototype.
  • Tails' AI is much simpler: he simply copies the moves that Sonic makes, and makes no attempt to keep up with Sonic.
  • If Tails dies, he will come back on-screen still in his death sprite, and will spin in whatever direction Sonic is facing in as soon as he hits the ground. This is because Tails can't fly yet.
  • Spin Dash is still a work in progress, as Sonic and Tails can only charge the Spin Dash once, and the sound for when Sonic spins in Sonic 1 is heard, as the Spin Dash sound hasn't been finished yet.
  • The full Blue Sphere game is unlocked when Sonic & Knuckles is locked on because both this and the Nick Arcade prototype use Sonic 1's serial number.
  • Genocide City and Death Egg, although empty, use the Emerald Hill palette.
  • Final boss music for Death Egg is in the ROM and is nearly the same as the final's.
  • Tails uses slightly different jumping and rolling sprites.
  • Sonic's sprites use the same palette as the final, but are Sonic 1 style. There are also unused spinning sprites in the ROM.
  • There is a bug where Sonic's pushing animations are used instead of his running animation.
  • 2P bugs:
    • Tails is only playable via 2 player mode.
    • Sonic may only pass the signpost.
    • Sonic and Tails both share the same life and ring counters.
    • Sonic and Tails still have to defeat the boss in Emerald Hill.
    • There is no countdown for Tails after Sonic passes the signpost.
    • If the 2P controller isn't used, Tails' AI will still follow and copy Sonic.
    • Even though the 2 player level music exists, 2 player mode's playlist is not yet implemented and thus the levels play their single player music.
    • Every zone can be selected for 2 player mode in the level select, except for Chemical Plant Act 2, Neo Green Hill, and Hidden Palace (forcing the game to load levels with water in 2 player mode results in a crash). However, loading any zone other then Green Hill (Emerald Hill in the final), Dust Hill (Mystic Cave), and Casino Night will result in a very strange looking mess of glitchy art tiles, as well as Tails' camera using very broken scroll data. This is due to 2 player mode's levels requiring more data than the normal 1 player levels, which means that zones not set up for 2 player mode will use garbage data instead of the necessary 2 player data. This behavior is also in the final game. However, in the final release, these zones can only be played in 2 player through cheating or hacking.
  • The SEGA screen does not show up during boot because of altering; but it can be present after a demo but it is the same as the SEGA screen from Sonic 1.

Neo Green Hill Zone

  • This zone is only zone playable without Level Select cheat.
  • Actually, Aquatic Ruin Zone is named as Neo Green Hill Zone. Not to be confused with the Sonic Advance level of the same name.
  • There are no enemies except the arrow-shooting totems.
  • The layout is half-completed.
  • There is a corrupted splashing animation consisting of misaligned bubbles instead of a splashing sprite. Tails has no splashing effects.
  • If Sonic gets out of the water during the countdown, the music will be changed to the Emerald Hill theme.
  • Water does NOT have any effect on Tails other than palette change.
  • If you finish this zone, you will be sent to Chemical Plant Zone.

Chemical Plant Zone

  • As with Aquatic Ruin Zone, the Emerald Hill theme plays if you get out of the water during a countdown.
  • The loop-de-loop platforms have octagonal edges instead of being flat, just like the Nick Arcade prototype.
  • The platforms which move across rails (most noticeably in Act 2) are much smaller.
  • Demo gameplay hasn't been rerecorded to fit new level design since the Nick Arcade build.
  • There is a badnik called Bubbler's Mother that drops Bubbler that was set to appear in this zone. It can be seen through the method of hacking.
  • This zone has no Badniks in its level layout. As a result, Sonic can only be killed by getting crushed by the moving blocks (which don't always crush properly), falling into a death pit, or by drowning.

Hill Top Zone

  • Sonic doesn't spin when going through tunnels.
  • There is no earthquake sound effect.
  • The background music runs at a slightly slower tempo than in the final.
  • Demo gameplay hasn't been rerecorded to fit new level design since the Nick Arcade build.

Green Hill Zone

  • In this Beta, Emerald Hill Zone is referred to as Green Hill Zone.
  • Demo gameplay for 2P Mode hasn't been rerecorded to fit new level design since the Nick Arcade build.
  • Demo gameplay for 2P Mode illustrates a bug: both players share the ring counter (when one player gains or loses rings, so does the other). They also share the same lives counter.
  • There is a snail Badnik that did not make it to the final ROM. Its art offset is at $7C514 (Nemesis compression, 26 blocks).
  • At one point, there is a hidden wall which is supposed to contain an extra life; it does but it is blocked off. The only way to get to it is by the use of Debug Mode.
  • This is the only zone with a boss. It looks exactly the same as it does in the final, but there are slight differences in its behavior:
    • The Eggpod drops straight down into the car rather than descending diagonally like the previous build.
    • When defeated, there are no explosion effects, unlike the previous build although it uses the explosions from Sonic 1. This proves that the explosions were taken out and the new ones from Sonic 2 final were added in somewhere in between this prototype and Sonic 2 CENSOR Prototype during development.
    • If Robotnik was facing left, he will not turn around as he escapes to the right.
    • The boss does not turn as early as he does in CENSOR Prototype and later: he goes all the way to the end of the road and back as opposed to halfway.

Metropolis Zone

  • Pistons don't throw you up as high as they do in the final, making this level impossible without debug mode.
  • Metal crushers do not hurt you unless you go underneath them when they come down.
  • Fire and lava have no effect.
  • Sonic falls through most of the rotating nets, but one of them does work (which suggests that the one working was the test object).
  • Sonic can rotate a nut upwards past the height of the supporting screw pole.
  • Act 3 has a diagonal lift that was cut from the final game.
  • There is a Fourth Act which is exactly the same as Act 3 except Sonic starts in a different spot. This can be accessed by hacking.
  • If you ride the platforms over the lava at the beginning of the act, when they go under the lava, so will you. They are also visible while under the lava.

Oil Ocean Zone

  • This zone plays different music from the final, which was later used in Casino Night Zone 2P mode, but the music for Oil Ocean can be played in the sound test. It's number 90 and 91.
  • The sun scrolls with the background, and is non-animated.
  • Wooden balls are embedded in the ground, and can be activated by pressing a nearby switch. They will pop up and move to the left at a fixed speed. Sonic can stand on these balls while they travel. They were dropped as a gameplay element from the final, possibly because nobody could think of a good use for them, but the chambers and switches can be placed with debug mode in the final, and both have the same behavior as in the beta. Wooden balls were seen in prototype shots of Sonic the Hedgehog's Green Hill Zone, and can be seen in this game's debug mode, but they cannot be placed.
  • Two seahorse enemies are found within the prototype ROM through hacking.
  • An unused, shoot-and-flee octopus enemy is found within the prototype ROM through hacking.
  • The oil splashing animation is missing and oil slides have no effect on Sonic.
  • A pipe in the level's background is sucking oil up instead of pouring it out.

Mystic Cave Zone

  • In this Beta, Mystic Cave Zone is referred to as Dust Hill Zone.
  • Because of the lack of objects, this level requires debug mode to completely explore the level.
  • Act 1 has a few odd platforming issues near the end. Other than that, layout wise, both acts are identical to their final counterpart.
  • It seems Act 1 was only used for object testing: Act 1 has a bunch of randomly placed objects at the beginning of the level, but once you get halfway through, the level is empty.
  • Act 2 is also devoid of objects.
  • The bridge object works in Act 1, but it uses a switch to open it instead of vines seen in later builds.
  • The robots don't exist yet in this build.
  • The level also uses music similar to the final version.

Casino Night Zone

  • Drastic art changes when compared to the final: This zone has a pink card-suit-based scheme with sky blue floors. The tile layout is pretty similar to the final, but many level pieces are broken or missing, requiring Debug Mode to go deep into the level.
  • There are no objects in this zone.
    • The only two objects in the zone's object debug list are a ring and a monitor.
  • There is a prototype of the Crawl badnik which can be seen by hacking the ROM, it remains as a lost sprite in the Final Sonic 2.
  • Many of the flipping tiles are missing or the outlines flash and the tiles remain stationary. With hacking, it is possible to implement the rotating tile, because they exist, albeit without its flipping format.
  • There are no Sonic, Miles or Casino Tiles. Instead, these are part of the layout tiles themselves.
  • There is a different sound for the bouncers that give points and disappear after three hits (that don't yet exist).
  • The background of Act 2 uses foreground layout chunks, making it somewhat harder to play Act 2.
  • The red bumpers that give 10 points per hit do not exist. If the object, obj44, is placed in the level, it instead places a solid wall, similar to the one from GHZ. Thus proving even further that Sonic 2 Beta is a build off Sonic 1.


Hidden content

Sonic Retro emblem.svg Main article: Sonic the Hedgehog 2 (Simon Wai prototype)/Hidden content


This Simon Wai prototype was presented to the Western Sonic the Hedgehog fan community in 1999, though had been distributed in various forms for many years prior to this date. Its release was pivotal in cultivating research into the development of Sonic the Hedgehog games in the years that followed. Sonic Retro's origins partly date back to Simon's initial documentation of the ROM in the form of the now-defunct The Sonic 2 Beta Page.

Yuji Naka claimed in an IGN interview that it this prototype was originally stolen from a toy fair in New York in 1992[1]. Copies were then mass-produced by software pirates (via the Super Magic Drive) and distributed on unlicensed Mega Drive cartridges across Asia and South America, passed on as the final version of the game. As a result of this theft, Sega temporarily changed their stance on journalists accessing pre-release versions of their games, forcing them to travel to a location of their choosing so as to ensure no further leakages could occur[2].

The ROM is thought to have been hacked to hide the Sega logo from showing when the game boots up (though it was not removed entirely).

Technical information

In Night mode, the Aquatic Ruin Zone (Neo Green Hill Zone) displays 114 colors on screen. In the standard Sonic 2 game, the stage displays 75 colors on screen.


Sonic the Hedgehog 2 (Simon Wai prototype), prerelease version of Sonic the Hedgehog 2 (16-bit)
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