If only the controls were responsive enough...
However the controls are just not quite up to the console-level responsiveness that a game that effectively plays like Ghosts-N-Goblins in Castlevania requires. Your character holds the sword-swinging position for about a half-second in the currently-facing direction even if you need to rapidly change facing the other direction. I.e., instead of rapidly turning so you can swing the opposite direction, your character remains facing the same way and MOVES in the opposite direction. Anyone who has spent years playing arcade and console games expecting the correct rapid movements will rapidly find this disappointingly stiff.
In short -- Super Meat Boy fans need not apply... ...at least until they improve the controls to correctly support a game that's otherwise a fantastic idea.