This game reminds me of the old Atari game Adventure. I enjoy the concept of being able to scout ahead to search for items and areas, but there should be a limit on how far away the round object is allowed to move away from the square player object, as there's little incentive to swap between the square and circle frequently. Maybe only being able to carry back a limited number of keys, which then you would *pass* to the square? Fighting the boss is also difficult. Also there were a few times where the path led back in on itself, and the character would get stuck in a wall after going through a door. All in all, this is an excellent idea that just needs a little work on the mechanics.
I love the little Zoey on the game over screen.