First, congratulations to Jay on the game release! Kudos!
Tried the demo yesterday evening (to ensure the game runs on my new rig) and was surprised about how well I remembered the "tutorial temple" from the old pilot (the old brain cells, both two of them, are still kicking!). I was also surprised (pleasantly) how the game holds no punches from the start, contrary to many modern games which are really easy in the beginning parts. My party was in pretty dire straights by the time I got to the main hall of the temple (with the icky pool) and that was just the first floor of the temple. Without the bonus Drama Star for having a PC incapacitated for the first time, I think would've been toast (those damn priests were rolling really good, crits left and right, grr!).
The Endurance mechanic is something I'm not quite sure if I'll come to like it or hate it. On paper, I really love it, but in practice it seems to be a bit, er, iffy. Granted, I've only played the demo part, but based on that, it seems the Endurance/Stamina/Mana/Whatever-it-was-called is a bit too slow to recharge and the Exhaustion mark will bite you in the backside quite fast if you tend to use your casters a lot. Even with my casters taking (R)ests every now and then in battles, they were still running quite low on the "casting juice" quite fast (and I did retreat to the entry chamber several times to fully rest). The first level-up helped a bit, I took the "perk" for less Endurance loss with casting, but it's still quite hard to get to grips on how to use your casters most efficiently (they were popping liquid naps like there was no tomorrow).
I feel the camera is set oddly low. I feel like I'm leading a party of halflings around. To wit, it's quite hard to spot anything in the niches of rooms when you're barely at their height. Maybe that's intended, but I'd really like the camera to be a bit higher.
Other than that, I'm enjoying Frayed Knights a lot and am looking forward to getting to play the whole game.