I've only just recently gotten into Act 2 but so far I haven't come across a single bug, actually. Seems very polished. It does require a bit of a Warhammer primer before coming in if you want to know what's going on though. The game does a good enough job of explaining things that are important within the game but a lot of the context and fine details will escape you if you don't know at least a little about the 40k setting at large.