The following is taken from the US manual of the game:
"Dr. Ivo Robotnik, (A.K.A Dr.Eggman),the mad scientist, is snatching innocent animals and turning them into evil robots! Only one tough dude can put an end to the demented scientist's fiendish scheme. It's Sonic, the real cool hedgehog with the spiked haircut and power sneakers that give him super speed.
Help Sonic fight hordes of metal maniacs and do the loop with the super sonic spin attack. Speed down twisting tunnels and swing over dangerous booby traps. Leap across lava pits and dodge burning rocks. Then splash through the chilling waters in an underground cavern. And if you're lucky, you can warp to the secret zone where you spin around in a floating maze! Your greatest challenge lurks in a secret lab where you come face to face with Dr. Robotnik himself!
Spin through space, loop 'till you're dizzy, save the animals and become the super hero! Be Sonic! Be atomic!"