Using the debug mode in Hidden Palace Zone, it is possible to hit Robotnik 256 times and he will explode.
This cartridge is the only gaming cartridge to ever feature "lock-on technology" (This type of set-up was used once before for the 'Game Genie' - an additional cart that sat between the cartridge itself and the console to enable the manipulation of code to gain extras like more lives or invulnerability). The cartridge has a cartridge slot on the top which you could plug in any Mega Drive/Genesis cartridge. Plugging in Sonic 3 allowed you to play Sonic 3 as it was meant to be, allowing you to play both games combined, as well as use Knuckles in the Sonic 3 stages (which had different routes than Sonic & Tails' stages), as well as Tails in the Sonic & Knuckles stages which also allowed Tails to become Super Tails for the first (and to my knowledge only, excluding the debug cheat in Sonic 2) time, he had the same abilities as Super Sonic & Knuckles, but he also had 4 invulnerable birds which would attack any enemy nearby. You could also become Hyper Sonic & Hyper Knuckles which were supped-up version of Super Sonic & Knuckles. If you plugged in Sonic 2, you could play Sonic 2 with Knuckles, in which they added extra areas that only Knuckles could reach, and it made the last boos more difficult as Knuckles can't jump as high as Sonic & Tails which limited the opportunities to attack. If you plugged in Sonic 1, you can play 1000 different 3D special stages after holding A, B & C and pressing START. Plugging in any other game would allow you to play 1 3D special stage, but that same stage is available when locking on Sonic 1.
When hooked up to Sonic 3 the level access cheat displays Hidden Palace Zone as Lava Reef Zone 4.
Tails does not appear in this game, however is picture is on the spinning sign at the end of Act I of each level. (If you pause the game at certain points).
Tails only makes an appearance when this game is hooked up to Sonic 3.