I originally played this game because you used my song for the background music, (excellent choice BTW) but I ended up really enjoying this game! It was quick, took me about 35 min, five deaths on level 30, and a little patience, but was well worth it. I will have to check out your other games.
If you were looking to improve this game, the only thing I would suggest is to create a random level generator similar to the Diablo games--I also realize that this would take a lot of programming as ONLY randomizing tiles, teleports, enemies, keys and doors would not be enough; a clear exit path would have to be guaranteed every time. Additionally, I think the amount of time that the player can use the grid should be time-limited per level to avoid using it all of the time (which I did).
Other than that, hurry up and make more. I get bored easily :)
P.S. If you want me to write another tune for the next one, let me know.