Very clever puzzles! But also they start very tricky! The biggest thing I'd like is really clear signposting of what you're aiming for because currently you often have to start by steathily looking at the end to get an idea of what you're aiming for. Either that or make sure that each room has only one solution so you know you haven't ruined a later part of a puzzle with a mistake early on.
Also it took me a while to work out you could go up stairs. That needs a bit more signposting for me. I would reiterate peoples comments about controlls moving with the camera and collisions.
Really fun game though!