The Death Egg, Dr. Ivo Robotnik's space station, has once again crashed on Angel Island after the events of Sonic the Hedgehog 3. Robotnik needs power the Chaos Emeralds to power it up again, and because of this, Sonic and Tails have to find the Chaos Emeralds before him so they can stop his plans of world domination. However, Knuckles, the guardian of Angel Island and the Master Emerald, was tricked by Robotnik into thinking that Sonic and Tails are after the Master Emerald, so he is equally determined to stop the duo. But while all 3 are going round with each other, who's gonna stop Robotnik? Written by
Did You Know?
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. See more
In Sandopolis Act 1, after the boss is defeated, for some reason, the boss music continues to play. See more