Simple; a great game.
This isn't an ordinary run-of-the-mill platforum game. I love the style of the graphics; it's simple, but gets the point across. No backgrounds or extra frilly stuff getting in the way of the fun. The concept is simple and great. The jump could be worked on, though. And there is a glitch in one of the levels.
Tweak it a little bit (keep the health system), and the sequel (i've seen that you made one) will be great!