My friends who've gone into 'normal' software development will work on things out-of-hours from time to time, especially if they're doing something interesting, and they're sometimes on call - but they're also making enough money that if they'd rather work a 4 day week, they can afford to.
My friends who've gone into game development report frequently working 10 hours a day Monday-Friday, and then going into work on both Saturday and Sunday. Or at least, they reported that the last time we saw them - you can imagine how hard it is to maintain friendships after a few years of such a work pattern.