If you buy Super Meat Boy through Valve's Steam service, you'll receive Half-Life's hideous (but sort of adorable) headcrab as a playable character. All non-Steam purchases on PC and Mac will receive a Goo from World of Goo. Either character will replace Gish as the first unlockable (via bandage collection) bonus character. As for which version to purchase, Team Meat is apparently very fond of Valve's digital distribution service, saying, "We LOVE Steam...like...a lot. MS is the hot chick you hook up with, Steam is the girl you spend your life with." We wonder where WiiWare must sit on that spectrum after those development challenges?