It's fantastic. I really like the use of Sonic 4 themes in it. The game delivers exactly on what it wanted to, and that is level design. Even Stealth had some issues with the spike timing in Marble Zone Act 3, and I did as well but not so badly, I think it's a bit unfair and it might be easier to some players to replicate and that's why it was overlooked, but the fact that the game gets harder or explores a way to create harder level design over the original STH is not bad.
