In Sonic and Knuckles, there are eight Zones. But only Super Sonic can reach the last Zone of the game. Only Sonic or Tails can play the second to last Zone, the Death Egg. Most zones have two levels, which are named "acts" in the game. At the end of every act 1, you've got to fight one of Dr. Eggman's robots, and at the end of every act 2, you've got to fight Dr. Eggman himself. There are small robots called "Badniks" in the acts. Most of them can be destroyed if you jump on them. If the badnik is destroyed, a little animal jumps out of it. 