This auction is for Sonic the Hedgehog 2 "Simon Wai" custom-made Prototype for Sega Genesis with Holographic label & Sega case + artwork.

Notes:

This game has no save features.

To access other levels in the game, a cheat code must be used, see cheats down below.

Since this was made from a prototype build, the game itself is considered very incomplete. But it's still a very cool part of Sonic the Hedgehog's history.

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 on any level that doesn't have water.

Debug Mode - C, C, Up, Down, Down, Down, Down, Up.

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. The game doesn't lock P2's inputs, however it also doesn't stop Tails' AI.

Tails cannot complete a level on his own, since the game only loads the signpost 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. This was also the case with the Nick Arcade build, in which Tails was disabled in that build's Emerald Hill, likely for the challenge from the Nick Arcade show.

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 ID 88 (which was the 1-Up sound in the Nick Arcade build and also the Extra Life jingle in Sonic 1) has since been overwritten with the Death Egg music 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, have been modified to use the new correct sound ID.

The underwater countdown music uses the Level Select theme for the same reason as the 1-up jingle. When Sonic gets out of the water, the Emerald Hill music begins.

Spike behavior is still 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. Animal Capsules do not exist yet.

Exclusively to this build, the game only ever loads Pocky (the rabbit) and Cucky (the chicken) in all zones; the remaining Sonic 1 critters are unused, while Sonic 2‍ '​s aren't in the ROM yet.

Zones

Without accessing the level select, the game allows you to play Aquatic Ruin, Chemical Plant, Hill Top, and Emerald Hill.