I downloaded the demo, and I can see that this game has potential, but it's not quite there yet.
Graphics:
Awesome. The black and white style was very well done, and it always had this bloomy look to it. I especially liked how when looking down a hallway, it seems pitch black, but it lightens up when you get close. I'm assuming this has something to do with Ply's mod. I also loved the shader on the window in the first level, it looked like an actual window!
Gameplay:
The framerate was great, as it never dipped below 30. However, the puzzles were pretty bland. While the game started off easy with the simple "pile up some boxes, break some windows", the difficulty never really progressed. In fact, there was nothing more than piling up boxes and jumping over platforms in the whole game. I understand that this is merely a demo, but I hope that the puzzles are much more advanced in the full game.
This game definitely has potential. With some upgraded puzzles and some music and sound, I can see it becoming a fantastic game. Best of luck!