Hot off the announcement of a brand new retail version of the game, The Binding of Isaac is about to join the 450,000 sold club. There's no doubt that creator Edmund McMillen is thrilled, considering he didn't think that many people would buy into a creepy game with permadeath that featured a little boy flinging tears at mounds of poop.
The low price point of $5 is probably a large part of it's success, enabling a ton of "why not" purchases that Steam is often known for. As for myself, it was easily one of my most anticipated purchases of 2011, given McMillen's track record and my love for Rogue-likes (especially ones inspired by Zelda!). Keep in mind that things can only go uphill from here for McMillen, with a planned expansion on the horizon and a potential 3DS version of the game.
Maybe now Isaac can afford to move out of his Mom's basement.