Sonic the Hedgehog CD prototype 510, referred to as CD Sonic the Hedgehog on the title screen, is among the first prototypes of the game Sonic the Hedgehog CD for Mega CD. This prototype was leaked by a group of fans called Sega Extreme in the summer of 2000. The game contains all the stages of the final game, but in a normal playthrough the player can only see the first three: Palmtree Panic, Collision Chaos and Tidal Tempest. The rest can be viewed through the Level Select. This prototype deviates in many ways from the final game.
Differences
Graphical
• A 3D SEGA logo displays while the SEGA sound plays.
• The Title Screen is very different:
- 320x224 mode is used, as opposed to 256x224 mode. - The SEGA logo is golden. - On the ribbon the title CD Sonic The Hedgehog appears. - The clouds appear on the left, the mountain with the face of Dr. Eggman is larger, the menu is top-down and there are fewer mountains. - Also appearing in the credits is Keiko Utoku, a singer in the Japanese and European Opening.
• In the Time Attack screen, the exit logo displays an image of the Little Planet and the chain attaching it to the mountain with Eggman's face
• At the end of a level Sonic looks completely different.
• The original game had 3 additional power-ups:
- Super Monitor: Sonic has increased speed and an invincibility shield. It has a red "S" symbol. - Blue Belt: Functions identically to the Super Monitor. Has the image of a blue ring. - Freeze time: Has the image of a clock. This does not work correctly, but its role was to freeze time for a few seconds.
• Amy Rose has larger eyes and quills.
• After completing the first 3 levels, screen that says "COMIN' SOON" is displayed.
• The lives counter is slightly higher than normal, and there are no zeros in the SCORE and RINGS counter.
• The flowers that come from each badnik are different.
• There are badniks in the Good Future of every zone.
