Hey @bloodpirat!
I tried your game for about 5 levels (I'll try again later, don't worry ;) ) and it's really hard... :)
The art style is really polished and the blood particles were made excellent, the sound effects are good too.
The only thing you may want to change is the controls, the controls are fine except jumping and running the same time, the character doesn't jump half the time...
Overall, you have done a really good job!
Have a nice day! :D