So the game was on sale/discount on US PSN and I decided to get it and finally play this game.
...and after beating it just a few minutes ago I...don't like it very much.
For one thing, the 'theme' of the stages didn't stand out, in Sonic 2 each stage's theme stood out and you felt you were playing in a Grassland, a chemical plant, ancient ruins, a casino zone, etc.
...in Sonic CD, the stages didn't feel like that to me.
I can't really say much about the layout and design of stages TBH, but the Time warp posts positioning irked me at times, not to mention how tricky it is in certain areas to gain enough speed to warp to the Past or Future.
...and man are the Special Stages hard @_@.
Furthermore, Eggman's battles weren't that interesting, not even his final battle, he was among my biggest letdown in the game.
I think I only died 2-3 times against Metal Sonic. I personally do like Plamtree Panic and metal Sonic's boss battle themes. Controls were pretty good too.
Overall...not among my fav. Sonic games. I had to play it though in order to give a fair judgement and see if I would like it or not though.