We're talking major parts for Sonic, Tails, Knuckles, Tom ... and 1993 before being introduced in the games in 1993's Sonic CD, originally the flagship game of the Sega CD, itself a CD-ROM ...

While Sonic CD has a rather simple and easy-to-overlook ... These events don’t necessarily need to happen before Sonic 2, but since neither Tails nor Super Sonic appear in that game, it is ...