For modern however, jeez where do I start, the first part isn't so bad but once you get to the part where you have to scale the building, it's TERRIBLE. The classic version isn't too bad, but has its problems, some areas slow you down to a halt and have you do a sorta puzzlelike thing with the wisp to proceed(great explanation I know), the pink wisp is a little awkward to control, and the level feels a little longer than it should. Sonic generations: Planet wisp, I'm going to count both acts as one stage, classic first.

Sonic unleashed(PS3 and 360 version, even though I do like the Wii version):Eggmanland, do I really need to say more? For all of those who are not enlightened, eggman land is a insanely long level with some unforgiving level design, one of those sled sections with terrible controls, many, many insta kill spots, and it's one of those levels where the werehog has no drop shadow, great.

Sonic 2:Metropolis zone: The unholy trinity(specially slicers) and the fact it has 3 acts, no one asked for a sudden 3 acts change compared to all the 2 acts, sega. I am far too lazy to list ALL so I'll list a few

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