It's awesome man! I love the graphics especially. It's really well done. I beat it not too long ago. You should also post it on www.gamejolt.com
if you haven't already.
My only critique, you should consider making the escape key deactivate all objects except a controller object, for a pause menu. That way, the user can pause the game and get back to it later, without losing any progress. Also the sound I hear that is played when you get hit by an enemy, is used in a lot of GameMaker games, I recommend using perhaps your own sound effect for that.
Other than those two small things, I have no complaints. Your game is challenging, but not unbearably so, and the duration is good. I like that you can double jump. It is a true work of art! Even the animation is great!