Sonic the Hedgehog 2 (Nick Arcade prototype)

From Sonic Retro

Revision as of 09:19, 27 August 2011 by SoundableObject (talk | contribs) (Levels: Expanded on Hill Top Zone problem for clarity)


S2b title.png
Sonic the Hedgehog 2
Publisher: Sega
System(s): Sega Mega Drive/Genesis

The Sonic The Hedgehog 2 Nick Arcade Prototype, released to the public on Nov. 7, 2006, is a prototype of Sonic the Hedgehog 2 for the Sega Mega Drive/Genesis, which features extremely unfinished zones. This cart, determined to be near exact to the one shown in two 1992 episodes of Nick Arcade, predates the more famous Simon Wai prototype. It was found and sold to drx in cartridge form for $1500 via a community effort.

In this version, only one zone can be normally played: Emerald Hill Zone. The rest of the Zones can be played only through a Level Select code. The level select screen is completely identical to the Japanese version of Sonic 1, and even contains the original Green Hill Zone, which is somewhat unplayable because of strange physics (caused by differences in how collision data is handled between Sonic 1 and Sonic 2).

The state of the build of this prototype shows that Sonic 2 is based off the original Sonic 1. Green Hill Zone is still in the game, Sonic 1 music is still intact, and the full Blue Sphere game is available when locked on to Sonic & Knuckles.

Download.svg Download Sonic the Hedgehog 2 (Nick Arcade prototype)
File: Sonic_The_Hedgehog_2_(Early_prototype)_( (519 kB) (info)

Various Differences


  • The title screen is the same as the Simon Wai Beta and Beta 4.
<flowplayer> File:Sonic 2 Nick Arcade prototype wall bounce.flv</flowplayer>
Sonic bounces back off a wall if he runs into it with a high velocity
  • If Sonic runs into a wall with a high velocity, he will bounce back off of the wall. This feature was canned sometime after this build, but the sprites it uses are still present in the Simon Wai prototype.
  • 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 hurt, just like in the later beta.
  • If Tails dies, the camera will follow him as he respawns until he goes off screen.
  • If Sonic & Tails are hit at the same time, lots of rings will sprawl out regardless of how many rings they actually have (provided the player has at least one ring).
  • The backgrounds of Hill Top and Chemical Plant don't move.
  • Invincibility doesn't show stars, but plays the music. The music and invulnerability lasts until the end of the act.
  • There is this 8bpp image whose purpose is unknown:

Green Hill Zone

  • This Zone from Sonic 1 is still available, 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.
  • Collision detection is there, but is very glitchy and detects hills that don't exist, among other things.
  • A Tails Life Monitor is present just as it is in Hidden Palace Zone.
  • You can see here that the Sonic 1 springs still are here in the game and fully functional; the springs in the Sonic 2 levels are different and match the final game.
  • Many badniks and and obstacles use glitchy sprites, including rings.
    • The Crabmeat badnik uses a lost sprite from Sonic 1
    • If one passes into Marble Zone (Chemical Plant Zone), the rings will still use the glitchy sprites they had in Green Hill Zone
    • The spikes used are the same ones from Sonic 2. They use the correct graphics (aside from the green outlines) when seen in Debug Mode but use glitchy graphics when placed or seen in normal gameplay
    • The boss for the zone also uses glitchy sprites
  • Tails can stand on the spikes without getting hurt

Marble Zone

  • This is Chemical Plant Zone, and it is heavily under development, with major differences in the level's design from either final or the later prototypes, and is very unfinished.
  • Chemical Plant Acts 2 and 3 have the same layout as Act 1, but have the ring and object layouts of Green Hill Zone 1.
  • It uses a pink background instead of a green background used in the later betas and final versions.
  • There are extra objects in the zone for Marble Zone in Sonic 1 accessible via debug, but they use garbled tiles.
  • There is a falling block for Chemical Plant also accessible via debug
  • The transportation tubes were apparently used in a different way, but they aren't functional in this build.
  • There is a prototype boss for this zone found in the ROM through hacking.

Spring Yard Zone

  • Actually Hidden Palace Zone, the zone pretty much as it is in the later Simon Wai prototype and the final version and it seems Sonic Team did not work on the zone any more beyond this point.
  • Act 2 has some leftover object placement from Green Hill Zone Act 2.
  • There is a third act which has water that constantly rises and falls. This zone loads Green Hill Zone Act 1's ring locations.
  • If under water in Acts 2 and 3 until the countdown starts and you jump out 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.
  • In Act 3 you get placed in the blocks, what makes the camera go crazy (after some button mashing you will eventually get placed into the level)

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 much of its collision detection and is therefore unplayable, a la Genocide City Zone. Using debug mode several people have found various strips of "land" but that data is often still just garbage.

Star Light Zone

  • Actually Emerald Hill Zone (which the later prototype confirms kept the name Green Hill Zone for a time) and is as the same as it was in the Nick Arcade video, with minor differences to the final level layout. Star Light Zone music plays in this zone.
  • This is the only zone where Tails is disabled, suggesting this particular version was tailored for the Nick Arcade show in order for the contestants not to have their rings lost by Tails. Tails can play in this zone via 2 player.
  • The layout is very different in Act 1, and slightly different in Act 2.
  • The boss behaves exactly the same as in the later prototype, but it does have explosion effects. These are the same as the ones from Sonic 1.

Scrap Brain Zone

  • Actually Hill Top Zone, this zone is also under heavy revision, as it finishes with a pipe leading to instant death because the screen-limit hadn't changed yet.
  • The playfield limits are still the same as they were in Sonic 1, but the level does not end at these limits. As a result, Act 1 cannot be played through.
  • The secondary collision array for Act 2 is missing, so as a result, loops don't work.
  • Second act crashes at about the midpoint. This is because, as Sonic 2 is built off of Sonic 1, the level event handler calls a subroutine from Sonic 1 that no longer exists (the transition between Acts 2 and 3 of Scrap Brain Zone). Final Zone crashes at the beginning for the same reason.
  • The lava doesn't hurt you in this prototype.
  • Green orbs are used as the weight on teeter-totters instead of a Sol without fireballs.
  • The lifts are not fully functional yet and partly broken

Final Zone

  • Hill Top Zone (matching behavior in Sonic 1, where Final Zone is tucked into a corner of SBZ2), crashes to pink if you continue onwards because the game is trying to access the Final Zone boss data which is not there, dead end backwards.

Special Stage

  • Same as Sonic 1
  • Unplayable (crashes to lila)

Art Differences

  • Sonic and Tails are in different symmetrical designs on the end signpost
  • Chemical Plant Zone uses a purple-pink accent in the background instead of olive green; buildings are also much lower
  • Seesaws similar to that in the final Hill Top Zone can be seen in Emerald Hill's object debug - An interesting connection because HTZ's uses Emerald Hill's art.


Cheat Codes

Note:All button input codes mirror those of the Japanese version of Sonic 1.
  • Level Select: At the title screen, press Up, Down, Down, Down, Down, Up, and Start.
  • Debug Mode: At the title screen, press C, C, Up, Down, Down, Down, Down, Up, then A + Start.
  • Level Select with Debug Mode: Activate the level select code, but don't press Start. Instead, let the demo play, then when it returns to the title screen, press C, C, Up, Down, Down, Down, Down, Up, then A + Start. Select a level and hold A until it loads.
  • Debug Patchcode: FFFFFA:0001. This patchcode removes the need to enter a Debug code. The level select code can be used to debug in any level.
  • Two-player Mode: Highlight an Act in the level select screen and press B + Start.
  • Restore Green Hill Zone Collision: With a Game Genie, enter the following codes:

Physical Cartridge

(from drx's Hidden Palace)

External Links

Sonic Retro
Sonic Retro release thread

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