So so far I'm fully done with Chapter 1 and 2 (Both Light and Dark worlds, A+ in all levels and the minus one levels). Is it possible to 100% the game with just Meat Boy? or some levels/picksup are only possible with other characters? --- "One must keep his friends close Raziel, and his enemies, even closer.." -- Legacy Of Kain: Soul Reaver
You can beat all levels with Meat Boy, but I can think of one warp zone that is not reachable with him, and perhaps a bandage or two, not sure. And, of course, a lot of bandages or warp zones are easier to access with different characters.
In any case, all levels are beatable with him for sure. --- "What kind of moron gets hit by a bus inside a shopping mall?" -Maria Torres, Trauma Team