Since this game doesn't really have to be "played" it would be nice to have a scrolling background of some kind. Maybe alternating every 5-10 minutes so we don't get totally bored. Also, if there were some way to select what type of attack the knight could do that would be interesting as well. Good idea though.
Demon lord is hard to kill. I push the arrow keys, and he still kills me somehow. Hints? Maybe make it so if you accidentily press the wrong button it isn't restart the level.