It's a good game. Feels quite reminiscent of Sometimes You Die, although 44 seems to have less to say than that game.
I'm sure I would have completed it by now, but I've died several times now, when I've been moving left or right while going up or down between two screens, because I've got stuck in scenery and/or the game has lost track of which screen I'm on. Quite frustrating with 39 keys collected.
This may just be an issue on widescreen devices due to the extra screen height, but I strongly recommend that you don't touch the walls while ascending/descending!