I couldn't really play much, I am quite bad with timing in jumping, but the game could have be a bit better development considering that is quite simple.
I would suggest at least to make 2 frames moving the Player's leg, add fullscreen and a button to restart the game (refreshing the page every time is quite annoying).
Lots of space for improvement if you wish to go on with the idea, that it's ok maybe as mobile game.
By the way, the monster is a minotaur, not a cyclopes :P