Have you ever thought, that there are tons of little animals left inside their metallic cages called badnicks? A lot of people completed this game, which objective was to stop Eggman and free the tiny critters. And we decided to help Sonic and Tails to actually free all the animals and destroy every single enemy in the entire game. So Sonic (with his ability to become Super Sonic upon collecting all the Chaos Emeralds) and Tails go on the rescue mission.
Sometimes badnicks do not spawn when you get closer to them from the right to the left. It can be easily fixed by going further to the left and back to the right.