This is awesome! Gameplay is great, music is amazing, story and dialogues are funny (easter eggs are a nice touch), and graphics look sketchy but I don't mind that at all considering that the game is free. BTW if developer would consider adding a "donationware" DLC - I would absolutely buy it.
I'm usually not really into hardcore platformers, but this game has just right amount of difficulty for me to be enjoyable. Except for boss fights, those are damn hard :)

I had some problems with initial controls config - default button mapping for controller is weird and when Steam Input was ON - game did not recognize my controller at all; so eventually I turned Input off and configured controller via in-game settings and it worked fine.