This is a nice concept! Definitely a creative take on the theme which I like. A few pieces of advice:
The player controller could use a little more work. I always manage to gain far too much velocity and go straight off the edge if I hold the button for a second too long. The jump and movement are far to hard to control and it just becomes frustrating.
The knife spinning around the player is annoying because I have very little control over if I kill an enemy or not, you should allow the player to have more control in the combat. You could also speed up the knife so you don't have to wait as long to kill an enemy. 

That's pretty much my major issues. Even just submitting a game is an accomplishment so you should be proud of that. Keep making games and good job!