- Back to: Sonic the Hedgehog CD (prototype; 1993-05-10).
The 510 prototype has a Sega screen, complete with classic jingle. This was removed from the final, likely as the Mega-CD BIOS already does the work in this regard.
The title screen was overhauled for the final game. In the 510 prototype, "CD Sonic the Hedgehog" uses a 320x224 screen resolution (versus 256x224) and lacks the scaling cloud effects. There is also no introductory animation, just a simple fade in.
The animated introduction has a different border, with the text "開発画面" (Kaihatsu Gamen, which literally translates to "development screen"). It also runs slower than the final game.
A scene involving the Eggman mountain does not exist yet, and is also absent from the PC port of the game.
This scene pans up towards Little Planet from the chain. In the final game, it is reversed, panning down instead.
The time attack mode uses a different "exit" icon than the final game, showing Little Planet rather than Sonic. The game again refers to itself as CD Sonic the Hedgehog. The default times are also set to 12 minutes rather than 15.
The title cards also read CD Sonic the Hedgehog, and the life counter in the HUD is misaligned.
In many ways the 510 prototype's level select is superior to that of the final game, as it lists all of the levels at once (including four blank ones which lead to Palmtree Panic act 1). The final nevertheless retains this layout, complete with the missing R2 and strangely placed WARP, OPENING, COMMING and SPEDEMO options (as well as Palmtree Panic good and bad future appearing after Tidal Tempest).
When starting a level, the screen locks in place for a bit too long, allowing Sonic to run off screen. The ring and score counters also don't appear until Sonic collects a ring or gains some points, respectively.
Get the time counter to 9:59:98 (one second earlier than the final game) and Sonic will die. Rather than display a time over message, the game will freeze.
The "past" and "future" icons do not appear in the HUD when the player hits a time warp sign.
Sonic can't drown in this prototype. There are no indications of him running out of air, and no countdown when it's low.
Enemies appear in good future versions of zones. They're disabled in the final game because, as the name suggests, it's meant to be a good future.
Coming within range of the goal does not cancel the time warp.
Giant rings don't take you to a special stage, they just make Sonic disappear at the end of the act. They also appear regardless of how many rings have been collected.