- Back to: Sonic the Hedgehog 3C (prototype 0408).
General comparisons
As a prototype for the cancelled compilation Sonic the Hedgehog 3 Limited Edition, the Sonic 3 branding is used all over the prototype. Even all of the music tracks are from Sonic 3.
The save system functions just like in Sonic 3, in that there are only six save slots instead of eight (for reference, the final Sonic 3 actually has 14 save images; 6 for S3 only, 8 for Sonic 3 & Knuckles), and lives and continues are not recorded. It is also possible to select Knuckles when starting a new game.
A saved game can be played past Launch Base Zone, but if the player exits the game after that the save file will be marked as "CLEAR", and only Zones 1 through 6 can be selected.
The level select screen is identical to the one in Sonic & Knuckles and Sonic 3 & Knuckles, however some Zones cannot be accessed. Enabling debug mode removes these restrictions, allowing you to enter them. These levels are:
- Lava Reef 3 & 4 (Act 2 Boss & Hidden Palace)
- Sky Sanctuary 2
- The Doomsday 1 & 2 (Doomsday & Death Egg Final boss)
- Bonus 1 & 2 (S&K Bonus Stages)
- Special Stage 1 & 2
Pressing 
while the game is paused returns you to the level select screen instead of the Sega screen.
None of the Japanese localisation changes have been fully implemented yet. The trademark symbols have not been removed from logos, and Tails' life icon is always "Tails". "Miles" will finish Acts though.
The ending sequences have yet to be implemented.
Gameplay comparisons
Monitor behavior is the same as in Sonic 1-3 in this build, where you have to jump on a monitor to break it, and hitting it from underneath makes it fall.
Monitors placed with debug are Lightning Shield monitors instead of "S" monitors.
Blue Knuckles still appears on the goal signpost when playing as Sonic or Tails. Likewise, a red Sonic is shown on the signpost when playing as Knuckles.
All Giant Rings in the Sonic & Knuckles stages are gold, behaving like the ones in Sonic 3.
Super forms
Tails and Knuckles have incomplete Super forms, since the art has yet to be implemented, thus Knuckles cannot turn Super by normal means. Likewise, Hyper Sonic is not in the game yet.
Due to Hyper Sonic not being in the game yet, "S" monitors will only transform the player into Super Sonic, and will still play the incorrect sound effect like in Sonic 3.
Some of Super Sonic's sprites are garbled when interacting with certain objects in the S&K zones.
The Super Sonic Water Shield bounce glitch from Sonic 3 is still present.
Graphics comparisons
All of Knuckles' underwater palettes are different in this prototype.
Knuckles' palette overwrites the black stripe on the bottom of Star Posts. This causes it to appear red instead of black.
Audio comparisons
The music for the title screen, mini-bosses, Knuckles, invincibility, and collecting 1-ups are all from Sonic 3.
Many sound effects are missing, especially in the Sonic & Knuckles Zones and when playing as Knuckles.
Has additional unused sound bytes of music at the following sound test codes: 24, 23, 32, 2D, 22, 21, 20, 1E.
Sound test numbering is different for most sounds. Lots of empty slots for sounds in the sound tester.
The Data Select music bug from Sonic 3 alone is still there.
If Lava Reef act 4 (Hidden Palace Zone) is accessed via Level Select it will use Sky Sanctuary music.
The lead echo track of Flying Battery Zone's Act 1 music will go off sync after the first loop, and will increasingly gain drag behind after every loop.
Level comparisons
References
while the game is paused returns you to the level select screen instead of the Sega screen.
