The Doomsday Zone has only one act.
Doomsday Zone using Super Sonic

Doomsday Zone using Hyper Sonic

After winning in Death Egg, it ( the Death Egg ) would explode. However, Robotnik escapes in a gigantic machine towards space and you would follow him. Doomsday Zone may be the most frustrating or even the most difficult zone of the entire game! However, it isn't difficult if you can control Super/Hyper Sonic well. ( Please be noted that normal Sonic cannot play the Doomsday Zone as he can't fly! ) There are two diffent types of missiles here and a blue coloured spike ball obstructing your path. Oh yeah, this zone moves rather quickly too!
There are quite a number of tips so click on this sentence to view them.
Midi file for The Doomsday Zone.