1) This game really could have benefited from some calming music playing in the background. As it stands, the game is so silent you could hear a pin drop.
2) I found an error in Room 4. In that room you can push one of the white blocks over a black box beneath a switch. Which is odd consider it's impossible to do this in every other room in the game.
3) This game really needed to have puzzles that would either prove to be more challenging for the player to solve or need more puzzle variety in order to keep the player's interest. As it stands, this game can be beaten in around 15 minutes or so on your first time through. And has no real replay value beyond beating the game faster.
4) It would have been neat if the game included a feature to calculate the length of time it took you to complete the game from beginning to end. And if it could offer a breakdown by puzzle.