This is fun. I also liked how you extinguish the torches just to have them re-lit again. I also found the game rather easy once I figured out that blood makes enemies suspicious and you should clean it after you kill someone. I eventually ended up showing myself to one enemy at time, drawing them from the group to a corner, hiding for a second to get them back to unaware (they loose interest really, really quickly) and then instakilling them with sneak attack.
The techniques are cool, but I never really needed anything but Harvest. I used Vanish once or twice to get out of trouble, but I would survive even without it. Conceal and Meditate have unfortunately never seen use.
Overall, I really like how this game works - the stealth mechanics are solid and even though the enemies let you come close enough for a sneak attack a bit too easily, I liked executing them in a fountain of gore. :)