Enjoying it so far (almost 40 hours) - love the lore and the way they have interpreted W40K universe - pretty much what I envisioned from playing TT years ago. I can't remember any rules though...I'm playing on normal, but I definitely find that I have to use my heroic acts quite often (and they are very powerful, which is cool and appropriate for setting). Cassia is a beast *zap*zap* - my own PC is not actually that great at dealing damage, she's essentially a sniper/bounty hunter, but mostly 1 shot per turn. The melee characters do very well. I took some PSY skills at start, and pumped up my WIS in preparation, but in retropsect I think that was a waste. I'm just shy of level 20 and so far my PSY abilities (I'm a telepath) have been somewhat supplementary - like blinding people and using staff/scream . But they do such minor damage (esp compared to heavy hitters) at my current level and enemy hp just keep going up, and up. I' now hesistant to go that route....I think I should have gone entirely with a ranage damage dealer build and pushed up agility, ballistics etc. Anyway, so far, so good, had some narrow escapes early early, but more or less have a handle on things.
Ship combat is a bit frustrating - the voidship moves like a beached whale, turning is a bitch. And you are always attacked by small agile craft and generally quite outnumbered.
Just established some small colony so dreading the management to come (always the thing I didn't like about Owlcat games).
I started playing more herteically, but seems you need to be a real ahole in many cases, so its not just really non-sanctioned stuff (e.g. dealing with Xenos, chaos agents etc). So often end up being iconoclastic, or when I'm in the mood, dogmatic (purge and burn!). Ended up killing a companion - kind of unintentionally by, a decision I made, but rolling with that ;-)
bugs: so far only bug I have (a very frustrating one - which i recall from PF games too) is that sometimes combat locks up, usually if I execute a move to square then do range attack from there. Happened 3 times, at critical places, when I was winning :/ - had to quit. However, I tried a trick to unfreeze and seems to work - select submit bug report (main menu near top I think) then submit it, the game then skips locked character turn but it will continue. At least worked when I tried it (found that somewhere online).