Nice overall work, but the jumping control feels completely broken. Way too high gravity, too short timeframe to successfully jump. It's said that the Mario developers constructed the animation system first whenever they started development of a new Mario game.

Further this Polygon article cites:

In fact, some develop games solely by feel. Independent developer Tommy Refenes claims to have spent two months getting the "feel" of Super Meat Boy exactly how he wanted it. Refenes states in a Gamasutra blog post, "everything from the weird 'friction' that happens when you change directions in the air to the 200MS delay that happens when you're on a wall and pull away is based on how it feels to me when I play it. None of these formulas are based on physics concepts, they are 100% based on feel."