Sonic the Hedgehog 2 (Simon Wai prototype)

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(Redirected from Sonic 2 Beta)


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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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  • 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.
  • 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.
  • 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.
  • Tails uses slightly different jumping and rolling sprites.
  • Sonic's sprites use the same palette as the final, but are Sonic 1 style.
  • There is a bug where Sonic's pushing animations are used instead of his running animation.
  • 2P bugs:
    • 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.
    • 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.

Neo Green Hill Zone

  • 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.

Chemical Plant Zone

  • As with Aquatic Ruin Zone, the Emerald Hill theme plays if you get out of the water during a countdown.

Hill Top Zone

  • 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

  • There is a snail Badnik that did not make it to the final ROM. Its art offset is at $7C514 (Nemesis compression, 26 blocks).
  • 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:
    • 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

  • 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.

Oil Ocean Zone

  • The oil splashing animation is missing.
  • A pipe in the level's background is sucking oil up instead of pouring it out.

Casino Night Zone

  • 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 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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Part of Sonic the Hedgehog 2 (16-bit) development

Sonic the Hedgehog 2 (16-bit)
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