Played the SP for around 3 hours and so far is ok. Visuals go from Bioshock's slightly less polished cousin to quite dated in places. The out door farm area was particularly poor.
Gameplay is fairly average FPS fair, the Veil and Veil powers add to the gameplay quite well and you need them to get to certain areas or to pass through dangerous places.
It gets a tad annoying when sniping enemies and you have hit them bang in the head three times and the game doesn't recognise the hit. It also happens durring bullet time, you can move through enemies one at at time pumping two or three point blank head shots and one of them won't die.
All in all it's been nothing more than an average FPS, with more polish and maybe more developement time it could have been a lot lot better.