GREAT!
The main game is incredible and very challenging. But what really got me is the Level Editor! I love games that allows me to create what I want, but your Level Editor is packed full of stuff and unlockables and at the same time not so complex to use. Amazing job! Ive spent about maybe 6 hours just on this game, best game on Newgrounds!
One thing that bothers me, is the jump button. I know its just me but this game would have been even better for me if the button layout wasnt like a fighting game where "up" means jump, when it comes to a Mario game, I have to have a certain button to "jump".
Overall, its an incredible game, and the "jump" criticism does not make me want to give anything lower than a 10 at all. ;)