#9: Sonic Chaos (April, 1993)
This game was the first 8-bit game to have Tails as a playable character. The story goes like this: Dr. Robotnik steals the red emerald and doing something to it that causes the other emeralds to lose balance and go into the special zone. The dimensional breach makes South Island(Sonic's home) start to sink into the ocean. It's up to Sonic and Tails to get all the emeralds, stop Dr. Robotnik from destroying the planet with his red emerald powered missiles and nukes, and save their home!
#10: SegaSonic The Hedgehog (September, 1993)
This game was an arcade game that featured 2 new characters: Mighty the armadillo, and Ray the flying squirrel. The only game Ray has ever been in, and the first of 2 games for Mighty. Sonic, Mighty, and Ray have to escape from Eggman Island because the dastardly doc had captured them.
#11: Sonic Spinball (November, 1993)
This game is played like a pinball game where Sonic is in his spin mode. Robotnik has taken control of Mt. Mobius and turns it into his Veg-O-Fortress. It has a roboticizer in it, that turns animals into robots. The only way for Sonic to stop the fortress is to make the volcano erupt. To do that, he needs to take the 16 blue chaos emeralds out of it, causing the volcano to lose it's stability and erupt! Robotnik realises the link between these emeralds and Mt. Mobius and creates a pinball defense system to keep Sonic from foiling his evil plot.