I love this game, my only suggestion is a longer and more detailed tutorial. The game itselsf is not difficult or complex in its mechanics, but as its so different from what we usually expect in first person games, its hard to understand until you play like 3 minutes. So a bigger and more guided tutorial could help the player understand what is happening since the start of the game.
Also, every time i get to the level selection menu and click level 3 and the click back the HTML game crashes. It doesnt happen with other levels.