Now that I've actually finished the game, constructive criticism!
- Buttons are broken, as I'm sure you noticed. You can have a crate sitting flat on the button but the door doesn't stay open, usually because the player walked off of the button on its edge.
- The way crates are carried in this game is not entirely intuitive. It's especially a problem when bringing a crate up the staircase in the penultimate level.
- As I've already noted, CTRL and ALT aren't the best keys to be using for controls in a web game.
- There was a part near the beginning where some text on the side was talking about a box with a lid and maybe you finding a way to get it open. I spent an irrationally disproportionate amount of time jumping at the painting on the wall, thinking it was the box and trying to see if I could open it. Perhaps that should've been a bit more clear :/