Wasn't aware of these guys. I didn't think many game companies had made it into YC. The only other game company I'm aware of is Koduco. Humble Bundle isn't a game company per say but is probably the most successful game related company that has been in YC. This thread was pretty useful (
http://news.ycombinator.com/item?id=1948870) and lists a few more. Are there any more?