1. Sonic the Hedgehog 2 (1992, Genesis)

The best innovations of the Sonic franchise came with Sonic the Hedgehog 2. The spin dash meant that Sonic could reach the needed speed to pass through loops and spirals on demand instead of having to rely on his momentum. This game gave us the first appearance of Super Sonic—the all-new, all-yellow, way faster (and much harder to control) version of Sonic achievable only by the most experienced and dedicated players. Special Stages improved with the new 3D-style tube stage, in which your success or failure depended on how well Tails could avoid getting hit by hazards as he tailed (heh) behind Sonic. But more than all of that, the introduction of Tails is, to me, by far the best thing that ever happened to Sonic because it meant my cousin and I could play our favorite game together for the first time.

We would race each other in head-to-head mode and I would often be the Tails to his Sonic in cooperative. My cousin had all four Genesis Sonics but it was Sonic 2 we played the most, mostly for its co-op mode but also because, for some strange reason, we simply preferred it to Sonic 3 or even Sonic & Knuckles. We played it for hours, often starting over once we got to the end even amid other options like Street Fighter II and Ms. Pac-Man. Sonic 2 was the one we always went back to, and the one I still always go back to.