I do believe it is considered a flop, but for some reason I've always thought of it as epic. It was sad when it and the Mega Drive were sold not with my consent, but a good day when I bought it again a decade later.
The graphics and sound was awesome, thanks to it using CDs.
Sonic CD is considered by some to be the best Sonic game, and its music was epic (unless you had the American version, then that's a shame). 'Work That Sucker To Death' as Robotnik's boss theme? Yes please. Brilliant that was.
Road Avenger came with the console, I think. That was a coo' first-person drive-through-things game (albeit a Quick Time Event game).
Also I remember Final Fight, the Streets of Rage style game where one of the characters was the mayor - a 6'4 beefcake wrestler with a glorious moustache. Enemies included André the Giant clones and dominatrixes, and the final boss was a guy in a wheelchair with a harpoon.
It also gave me the experience a few years ago of what I consider the worst game I've ever played (Cobra Command).
One of the stand-out games I haven't played yet is Night Trap, what with it being £20. Played Time Gal though.
awful games. sonic was pretty good. and a terminator game. a few good rpgs too
Sonic CD is the best Sonic 2D platformer by miles. Road Avenger was ace too. Had a few other games on the Mega CD, my fave being Jaguar XJ220. It had a track designer and everything!
It had Snatcher, a quality Hideo Kojima game. Not really played much else on it apart from Sonic CD though.