In an interview with VG247, Techland‘s Marcin Kruczkiewicz, who’s currently Hellraid‘s producer, declared that game has “almost infinite replayability” thanks to the Game Master.
This is meant to be a similar system to Left 4 Dead’s AI Director; in Marcin’s words,
It provides players with new experiences when they re-enter a level to complete sidequests or replay a mission in co-op
The Game Master will spawn different sets and types of enemies, also placing loot and treasure maps differently each time. While playing co-op, it will also take care of randomly generating competitive challenges between you and your friends.
Hellraid currently does not have a release date. It’s targeting PC, PS3 and X360 for its launch, although Kruczkiewicz mentioned that a port on PS4/XB1 is entirely possible.