I agree with the people saying the animation was unpolished. It felt stiff, robotic and angular. The jumps aren't "airy" or natural, they're stiff hops that really don't capture any of the game's death-defying leaping. Actually, that's pretty much the whole thing: stiff, angular and simply doesn't flow. Stuff happens, and some of it was intresting, but since everything happens stiffly, one thing at a time without any real flow, it didn't work. Character animation wasn't good either. I'm not sure there even is any half of the time, instead of just zooming the cube around. Some spit and polish would have gone a long way towards making this more than a lackluster project.
Oh, and the nondescript, bland music.
Meatboy is about energy, about the feel of it, about movement. It has a certain athmosphere, which this animation didn't really grasp. Still, though, it was a good effort.