If you picked up Super Meat Boy on Steam (and being a hardcore gamer you've probably already finished it, compared to me), you might want to check your library - the game has been expanded to Super Meat World, which means another 140 levels to bang your head against. You'll need to collect 20 bandages (which is 18 more than I ever managed to get before I gave up) to get access to them, though.
The levels have been created by different developers and players of the game, so get ready for some real challenges ahead.