Think you're good at platformers? Donkey Kong Country was too easy?
Nothing can prepare you for SUPER MEAT BOY. You'll need to have strong fingers, lightning reflexes and the ability to resist the urge to put a hole through your monitor. Somehow still manages to be fun, and the soundtrack is excellent.

Might be the best game I've ever played. Get it.
Some suggestions:
- Always have an assault rifle for the boss fights, even on pacifist runs
- Don't reload saves to change story decisions, you'll want to play it a few times anyway
- Look around for all of the side missions / information

Is this a game? It might seem too much like work, but this is difficulty on a cerebral level rather than twitch muscle memory (I'm looking at you Super Meat Boy). The satisfaction of watching your uber-complex machine finally work is what makes it good, but the music, art, and even a story wedged in the cracks make it great.