It's the damndest thing. Each time I play Sonic CD, I hate it a little more.
https://youtube.com/watch?v=AQzuCZfSWyk:66s
This is basically Sonic 1: Hard Type. With the running 'gag' of placing springs/spikes in the final stretch before the goal. Flying enemies that clip through walls. Precision platforming with floaty controls. I tried to use save states to get all the time stones, and I still ate shit. Ironically, Sonic is too
slow in these sections, and the UFOs have unclear hitboxes. There is no way to beat those final two sections without brute force and luck.
The zones lack identity. They're all remixes of Sonic 1 levels. Stardust Speedway is the iconic one. But it's the most frustrating level by far. The race with Metal Sonic is cheap as all hell. You find yourself jumping every few feet to avoid oncoming obstacles. This is not a speed or platforming contest.
The best thing I can say about it? Getting all the time stones will cause all enemies (well, most of them.... it's kind of unclear) to turn into flowers as soon as they spawn. But it's not worth the hassle. And you see why future games had multiple entrances to the special stage.