If you're somehow still on the fence about The Binding of Isaac for some reason you can now check out a flash demo of two levels from the game on Newgrounds. I don't know HOW you weren't sold after reading my review of the game, the names of the people involved, or the insanely cheap price but let me warn you now: don't play the demo unless you have $5 available because you won't be able to resist buying it.

Go play the demo now if you must, or just straight up buy the game. I've beaten the full game twelve times already and I still haven't found everything.