The Sonic News Networkhas a more detailed article located here.
Sonic & Knuckles is a 1994 video game, published and developed by Sega, released for the Sega Genesis. The game marked Knuckles' debut as a playable character.
Sometime after Sonic's story, an EggRobo attempts to kill Knuckles the Echidna with a well placed bomb. Knuckles gets angry and a chase begins. After getting to Hidden Palace Zone, Knuckles goes to Sky Sanctuary Zone only for the EggRobo to catch him. Mecha Sonic then shows up and tries to kill Knuckles, only for the latter to glide away, causing Mecha Sonic to destroy EggRobo. The two then battle with Knuckles then winning only for Mecha Sonic to enter his super state using the Master Emerald he had stolen. Knuckles then wins a though battle only for the platform to collapse. Sonic the Hedgehog then shows up in the Tornado and saves Knuckles. Knuckles the places the Master Emerald back at Angel Island restoring it’s flying state.
- Mushroom Hill Zone
- Flying Battery Zone
- Sandopolis Zone
- Lava Reef Zone
- Hidden Palace Zone
- Sky Sanctuary Zone
- Death Egg Zone
Lock-On TechnologyEditSonic & Knuckles is the other half of Sonic the Hedgehog 3, combining the two makes the complete game Sonic 3 & Knuckles. It is also possible to connect Sonic & Knuckles to Sonic the Hedgehog 2, allowing you to play through Sonic 2 with Knuckles. Connecting Sonic & Knuckles to any other Mega Drive allows you to access Blue Sphere. It's the same as the special stages and allows you to choose Blue Sphere stages on the main menu.
Debug Mode: With Sonic 2
Go to the options menu and play the following songs from the sound test 1,9,9,4,1,0,1,8. Choose any level, then hold A and press Start to activate Debug mode.