This is a relly cool idea. Having to think about which keys to use when so you can still play the game in later levels. I love the idea.
Sadly, it didn't work very well for me. The monsters did nothing (even when I touched them nothing happened). And I didn't need to assign the controls to any keys. I could just keep the ones from the previous level, thus removing all challenge from the game (of course it was a lot more fun, when I decided to not exploit this bug). And the last story bit seemed to end prematurely.
So, all in all a fun game with a few bugs (the worst of which can be easily ignored by the player to not ruin the fun).