Edmund McMillen, developer of The Binding of Isaac, announced that the title has moved over 700,000 copies on Steam, according to Joystiq.
“Who would have thought a game about an abused child fighting off his mother with his tears could ever sell 700k copies in less than a year?” McMillen said. “Not me, that’s for f*cking sure.”
The game’s expansion, Wrath of the Lamb, helped sell a fifth of that number in the last three weeks, he said.
In addition, McMillen said that an update to the DLC will add more “items, bosses, enemies, music, secrets and a very hard to attain final ending cut scene that should shed some light on the games story even more.”