Sonic CD
Even if the Sega CD was very short-lived, it gave us Sonic CD, a brand new 2D platformer separate from the mainline series that was still incredible in its own right. It featured a new story centered around Sonic rescuing Amy and Little Planet while confronting a new foe in Metal Sonic (complete with some great animated cinematics). There was also the new time travel mechanic where each zone had a past, present and future variant, complete with remixed music.
Going back to the past and destroying transporters to produce a good future for each zone was key to unlocking the best ending. Though its music was a hot topic back in the day due to the North American tracks being completely different, it’s still very good. Despite Sonic 1 to 3 and Sonic and Knuckles garnering most of the spotlight, Sonic CD is still a long-standing classic with exceptional depth.
