This subpage is for the first prototype of Sonic the Hedgehog 3.
- Many leftovers from Sonic the Hedgehog 2 and Sonic CD are in the coding.
- As with Many very early Sonic the Hedgehog 3 prototypes, rather than having a save option set up like how it is in the final, it's rather more of this: You can start a new game by selecting "new game", and if you leave a Zone (on any Act of the zone), if you select Continue, you'll be able to continue in the Zone and Act where you left off. However, anytime you select New game, all data from continue will be erased.
- The options menu from Sonic the Hedgehog 2 is used, however, it does have some differences:
- The 14 continues cheat will crash the game
- The Stage Select is already activated and available from the start.
- The game lacks 2 player Mode, if you do access the 2 Player Menu (misspelled as "2 Palyer Menu"), trying to access a 2 Player zone will crash the game.
- The zones have different names and different placements.
- The only way to become Super Sonic, is with the code from Sonic 2, which would give Sonic all chaos emeralds without having to go through the Special Stages.
- Sonic 2 music is used for the 1-up and continue screen.
Angel Island Zone
Mystic Mine Zone
- Mystic Mine Zone is an early name for Endless Mine Zone.
Marble Garden Zone
Egg Carrier Zone
- Egg Carrier Zone is an early name for Flying Battery Zone.
- This zone is not accessible normally by Knuckles.
Carnival Night Zone
Robotnik Base Zone
- Early version of Launch Base Zone.
Azrule Lake Zone
- Early version of Azure Lake Zone
Mushroom Valley Zone
Desert Palace Zone
- Early version of Sandopolis Zone
- Save icon is different from the icon in the prototypes and the final, in the prototypes, it shows some sand, with a daytime sky. The save icon used in this version is a Pyramid (like the one used in Act 2 and 3.)
Vegas Park Zone
- Early name for Balloon Park
Gene Gadget Zone
- Early version of Chrome Gadget Zone
Lava Reef Zone
Sky Sanctuary Zone
- Knuckles goes to Sonic's version of this zone, and goes on to Death Egg.
Death Egg Zone
- Knuckles goes through this zone.
- If accessed through the level select, it'll show up as "Doomsday Zone".