The Doomsday Zone

The Doomsday Zone is the final level of Sonic & Knuckles and Sonic 3 & Knuckles. The level only playable by Sonic and you must have all of the Chaos Emeralds to play the level. The level involves the chasing a huge ship made by Dr. Robotnik through an asteroid field. To defeat the ship you must make the missiles hit its "head" and avoid the ammunition it shoots. After you hit the head 8 times, the ship explodes and a giant robot similar to the Sonic 2 final boss in design with a jetpack. It releases bombs when you get close. You must mangage to get close to it and hit him 8 times to beat the level. The level gives you 50 rings at the begining and transforms you instantly into Super Sonic or Hyper Sonic if you have all of the Super Emeralds.