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Sonic 2 Prototype Summary

Facts regarding the prototypes have been compiled into this document. Significant bits are in bold. This is not meant to be a complete list of differences between the prototypes and the final version. Insignificant details or way-too-obvious discrepancies are not included.

Sonic the Hedgehog 2 Nick Arcade Prototype


  • If Sonic runs into a wall with a high velocity, he will bounce back off of the wall. This feature was ultimately canned, but it uses unused sprites that remained in the later beta.
  • Each Zone uses music from Sonic 1, further proving that Sonic 2 was built from Sonic 1.
  • There is a large amount of raw code contained within the ROM.
  • Tails can lose rings for the player if he is hit by a badnik.
  • Similar to the other prototype if Sonic & Tails are hit at the same time lots of rings will sprawl out regardless as to how many rings they actually have (Provided the player has at least 1 Ring)

Green Hill Zone

  • The zone from Sonic 1 is included, with its level art converted to Sonic 2's format (128x128 blocks rather than Sonic 1's 256x256s) and the necessary changes have been made to make loops work.
  • Green Hill has collision detection, albeit it's very glitchy, detecting hills that don't exist, among other things.
  • A Tails Life Monitor is present just as it is in Hidden Palace Zone.

Marble Zone

  • Actually Chemical Plant Zone, the zone is heavily under development, with major differences in level design from the final or from the later prototype, is buggy and unfinished generally.

Spring Yard Zone

  • Actually Hidden Palace Zone, the zone pretty much as it is in the later prototype and in the final since no work was ever done to it throughout its lifetime.
  • Hidden Palace Act 2 has some leftover object placement from Green Hill Zone Act 2.
  • There is a third act, as well, which has water that constantly rises and falls. This zone loads GHZ Act 1's ring locations.
  • If you stay in the water in Acts 2 and 3 until the countdown starts and come back up, the Labyrinth Zone music will play.
  • The level of water in Acts 2 and 3 can be controlled using up and down on the 2P controller.

Labyrinth Zone

  • An empty zone, it loads Marble Zone's ring layout and Chemical Plant Zone's artwork, has Labyrinth Zone's rippling effect. Third act is as SBZ3.
  • Labyrinth also lacks collision detection and is therefore unplayable, a la Genocide City Zone.

Star Light Zone

  • Actually Emerald Hill Zone (which the later prototype confirms kept the name Green Hill Zone for a time) which is as it was in the Nick Arcade video, with minor differences to the final level layout.

Scrap Brain Zone

  • Actually Hill Top Zone, this zone is also under heavy revision, as it finishes with a pipe leading to instant death. Second act crashes after a section which ought to have an earthquake effect.

Final Zone

  • Hill Top Zone (matching behaviour in Sonic 1, where FZ is tucked into a corner of SBZ2), crashes to pink if you continue onwards, death pit backwards.

Sonic the Hedgehog 2 Simon Wai Prototype


  • Sonic 2 was built based on Sonic 1. Therefore many Sonic 1 elements were carried over to this prototype.
  • This is a very early version of prototype. It's more of an "alpha" than "beta".
  • The prototype ROM has been tempered with by pirates, who have removed the Sega and Sonic Team credit at startup.
  • Sonic 1's "Sega" logo and voice is played after a demo or game is over.
  • Holding up or down keys for a while will not temporarily make Sonic look up or down.
  • Getting 100 rings plays Death Egg music.
  • Canceling out-of-breath countdown plays Emerald Hill music.
  • Invincibility plays Super Sonic music.
  • Super Sneakers, while still does the job, only speeds up the zone music a little bit.
  • Tails can destroy monitors, with the effects applied to Sonic.
  • Tails loses rings on Sonic's behalf.
  • Tails does not actively seek for Sonic but merely copies Sonic's moves with a constant delay.
  • When Sonic and Tails are attacked at the exact same time, massive loads of rings come out.
  • Tails cannot fly.
  • Tails uses Sonic's icon in 2P mode.
  • Tails does not walk up to Sonic when a level begins.
  • Spin Dash charge-up sound effect is the same as normal spinning.
  • Spin Dash release has no sound effect.
  • Objects placed are vertically flipped if Sonic is upside-down before entering debug mode.
  • Restart points can be placed using debug in certain zones.
  • Some zones' music are playable in level select screen, even though their names don't show up in the level list.
  • There is a prototype screenshot right in the Sonic 2 manual.

Chemical Plant Zone

  • Corners of loops are shaped differently.
  • An earlier prototype has different layout.
  • A background building is different in an alpha prototype.
  • An unused animation of Robotnik getting splattered by blue chemical is found within the prototype ROM through hacking.

Green Hill/Emerald Hill Zone

  • When fighting the boss, Sonic's graphics are messed up if he has invincibility or shield.
  • Boss flies straight down, instead of coming from the right as in final version.
  • Boss has no helicopter sound effect.
  • You can place a lost sprite, the high-tech star post, in this zone through debug.
  • An earlier prototype has different layout.

Hidden Palace Zone

Dust Hill Zone

Hill Top Zone

  • Sonic doesn't spin when going through tunnels.
  • There is no earthquake sound effect.

Neo Green Hill/Aquatic Ruin Zone

  • Water level is shallow.
  • Sonic's water-splashing animation is messed up.
  • Tails triggers no water-splashing animation.

Metropolis Zone

  • Pistons don't throw you very high up.
  • Metal crushers and fire cannot hurt Sonic.
  • Sonic falls through most of the rotating nets, but one of them does work.
  • Sonic can rotate a nut upwards pass the height of the supporting screw pole.
  • Act 3 has a special lift that was cut from the final game.

Oil Ocean Zone

  • The sun scrolls with the background, and is non-animated.
  • Wooden balls did appear in Sonic 1 prototype.
  • 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.

Wing Fortress Zone

  • Known as Sky Fortress Zone at one point during development.
  • Music is present in our prototype.

Genocide City Zone

  • Level is empty. Presumably canned at the very early stage of development.
  • Apparently, no screenshot of this zone, mock-up or otherwise, was ever published.
  • There's a slight graphical glitch involving a purple object in 2P.

Wood Zone

  • The level plays Metropolis Zone's music
  • There is more level layout but is inaccessible in normal game play.

Sonic the Hedgehog 2 Prototypes 4, 5, 6, 7 & 8


  • Sonic and Tails' Sprites have been changed to those of the final
  • Beta 4 can best be described as the version present in the Sonic 2 Manual. It was also the last build to have the beta title screen
  • Hidden Palace Zone has been removed, and we get the same garbled mess as the final
  • The Special Stages in some of the prototypes are completely different than those in the final.
  • The Sonic 1 spike bug is still present in Beta 4
  • Some sound effects are different than the final
  • Level layouts differ slightly, but for the most part are the same as those in the final
  • Sonic has small invincibility Stars that trail behind him while invincible in some of the prototypes
  • Wood Zone and Genocide City are completely gone
  • The game is now playable from start to finish

Zone Differences ( )denotes prototype version

Emerald Hill Zone

  • (04)-Same as the Final, excluding a bug that causes you to fall through some of the tiles and die in EHZ1.

Chemical Plant Zone

  • (04)-Again same as the final, only the "massive shortcut" to the CPZ2 boss contains an Extra Life instead of Invinciblity

Aquatic Ruin Zone

  • (04)-There are a lot more Grounders present, or at least it seems that there are, Spring in act 1 is placed slightly back from a ledge, so you drown.
  • (04)-There is a bug that allows you to walk through the bricks if you go fast enough, and fall.

Casino Night Zone

  • (04)- Different Sound Effect Plays on the Slot Machines
  • (04,05,06,07,08)- CNZ now uses the tiles that are in the final version
  • (04) There are a lot more of the blue platforms that crush you. these were removed in the final to avoid frustration.

Hill Top Zone

  • (04)- When you die, you fall considerably farther than in the final
  • (04)- In Act 2, the wall containing the Invincibilty in the room where the lava rises is sealed off
  • (04)- In Act 2, there is a flame badnik at the beginning of the level, he doesn't exist in the final

Mystic Cave Zone

  • (04)- Some of the Spikes are set lower into the ground than in the final.
  • (04)- In act 2, there is a middle platform at the beginning where the 2 bumping platforms are located. this was removed in the final
  • (04)- Hitting your head under the bridge at the end of act 1 causes you to die, this was fixed in the final
  • (04)- There is an extra life instead of invincibilty where the rotating boxes are in act 1.

Death Egg Zone

  • (04)- Silver Sonic is considerably slower while descending in the prototype
  • (04)- No Boss music or final boss music plays, just the death egg overture
  • (04)- 1 hit kills the final boss
  • (04,05,06,07,08)- The Final Boss' position is slightly more to the left of the screen than in the final