- Finish all levels with A+
- Get 100% in Forest
- Get 100% in Hospital
- Get 100% in Factory
- Get 100% in Hell
- Get 100% in Rapture
- Get 100% in The End
- Get 100% in Cotton Alley
- Platinum Boy (true 100% achievement, all levels including glitch, all bandages, all warp zones)
- Die 1000 times
- Die 10000 times
- Die 20000 times
- Finish certain levels in certain conditions (specific character, below a crazy time, ...)
The "Die x times" achievements will be reached no matter what by most people, but it's nice to get an achievement for trying.
The really frustrating achievements such as the ones where you have to finish a whole world without dying seem rather useless to me. Even though I have Golden God, i will never bother with them. It's just too time consuming and frustrating.
1. Castle Crashed! Escape Dr. Fetus' flying fortress in the light world without dying once.
2. Recipe For Pain! Create 50 levels in the Level Editor.
3. Warped Characters! Complete all the Character Warp Zones without stopping.
4. Running's for wimps! Complete a whole chapter without running.
5. Who needs friends! Complete a whole chapter without using a character other than Meat Boy.
These achievements are probably near impossible.

Actually I've completed all chapters using just Meat Boy (except Cotton Alley of course). I only used Ogmo for a couple of bandages and a warp zone that were impossible otherwise.