Yeah, most 2-D levels suck pritty hard. It's true. SRB2's 2-D mode plays rather well, but it's got one problem.
Acceleration.
If it was coded that you did not accelerate as fast in 2-D mode, screw the camera, it would all work better anyways. You speed up too fast, and your at full speed in three seconds. It's not physics, thouse are fine. Make it so you don't go so fast in 2-D mode and you'll have a good time. Yes I know "But I wanna go FASSSTTTT." Well, do you wanna play a 2-D level? "Yes." TOO BAD. Only a few 2-D levels let you go fast, and most of them suck, a few golden exceptions, but otherwise, NO.
Just slow it dow man!