Just played through, really well done. Looks great, I especially liked the floating fog/lens flares on top of the scenes. I assume those dark spots on the walls mean there will be quite a few more levels in the finished product?
It is a bit mysterious until you "find" the puzzles, but then it clicks. The one-click interface reminds me of Myst... just click around until you get an idea of what to do. Maybe some guide or hint would help people navigate?
Finding the desk was the key for me: perhaps that would be a good entry point to the scene? I spent a while looking around the walls before noticing the desk in the center of each room.