I am very critical of Jamie Bailey's coding. Most of the time he always tries to either half-ass things or make incredibly complicated code that does things completely wrong. Many of these things are prevalent in Time Attacked: Uneven gravity (springs make you fly up and decelerate fast, while you fall slow), timer events (especially evil), glitchy ramp physics, just to name a few.
I remember how in Sausage Roll Islands, he made this really wonky and weird system for the 3D palmtrees, which seemed to make them look more like they were dancing than they were passing over your head. He could have just did simple positioning using multipliers. Now, don't get me wrong. I don't hate the guy, I just wish he would change his coding style. And Time Attacked is still nice, because it's got cool cutscenes (even if they consist of 98% path movements, which are evil!) and its graphics are pretty good - definitely one of his strong points.
Retro Sonic seems to be pretty cool, too. The current demo (which is kind of old now) is pretty glitchy, but at least the creator admits it and has decided to redo the engine. Though there's the small matter of its release date. When will the new engine come out, anyway?