This article pertains to the beta elements from Sonic & Knuckles.
The True Doomsday Act 2
The actual Act 2 of The Doomsday Zone is inaccessible by normal means unless a glitch is used. The level is empty, except for a few chunks off screen. Due to there being no Rings in this area, the player will die.
|Super Sonic Slot
|Reel image for the slot machine Bonus Stage.|
|F-Ball||An unused gumball intended for the glowing spheres for the Bonus Stage. It can be placed using Debug Mode, but it does nothing.|
|S-Ball||An unused gumball from Sonic the Hedgehog 3 is found again in the glowing spheres Bonus Stage.|
|Platform||An unused platform intended for the glowing spheres Bonus Stage. Using Debug Mode, It can be placed in the stage and also be stood on.|
|Death Egg Holggram Projector||A machine that displays a hologram of the Death Egg, which is a reference to Star Wars. It can be found by hex-editing a savestate of Death Egg Zone's Act 2.|
|Hei Hou Peices||This object has no functionality and acts like a solid block. It is found in the Slot Machine Bonus Stage using Debug Mode and it appears to be based on the slot.|
|Hei Hou Peices||A set of unused sprites, for the Mushroom Hill Zone Act 1's mini-boss, can be found in the mini-boss object data. Some sprites have minor differences from the final version. The body and head are displayed as separate sprites here, unlike the final version of the boss.|
|FBZ2 Boss Head||A sprite from Flying Battery Zone 2's boss which goes unused due to a
programming oversight. It can be restored by using the Pro Action Replay code and it can be seen when it does its swinging attack.
|Egg Golem Piece||A kind of screw that should complete the body of the Egg Golem, the boss of Sandopolis Zone Act 2, is not present. Its sprite is loaded and the object has a sub-value to load it.|
|LRZ2 Stepping Stone||A lava stepping stone for Lava Reef Zone Act 2. Though the stepping stones only appear in Act 1, they do not appear anywhere in Act 2, thus this Act-specific sprite goes unused. It can be found and placed in Debug Mode.|
|Eggrobo Jumping||The Eggrobo do not jump in this game.|
|Knuckles intro cutscene||An unused Knuckles cutscene sprite for Mushroom Hill Zone Act 2 when hanging onto the Flying Battery ship.|
|Black and white Knuckles||Just like Sonic and Tails, Knuckles also has a black and white version of his death sprite, which is also unused.|
By hacking the game, a savestate can be found of a file for Tails and he can be enabled by using a PAR code of FFFF09:02. While he is playable, almost all his sprites are missing. The only sprites that are available are Tails running around the collapsing pillar at the end of Sky Sanctuary Zone, along with Lave Reef Zone with the same context, and his transformation sprite.
At one point in development, Super Sonic was supposed to have his own Insta-Shield which was superior to its predecessor. This Insta-Shield would be activated the same way as the Insta-Shield, except once activated, it would release a golden wave of energy instead of white that had a greater range and would last a whole second before having to recharge for about two seconds. This was removed because if it is used, the game will freeze for about three minutes and for some unknown reason, send Sonic to Hidden Palace Zone where the game would subsequently crash. (The move was found in the sprite files)