Like Left 4 Dead, which so clearly inspired it, Warhammer: End Times Vermintide [official site] is getting a cooperative wave survival mode in a free update. You know, a ‘be swarmed by hordes of increasingly tough and numerous monsters’ sort of a mode. Developers Fatshark mentioned plans for a survival mode last year, and now have more to say about when it’ll launch, what it’ll offer, and what will cost money.