Here're my two cents:
Cent One: There are some definite clutter issues with the interface and HUD, especially on the instructions screen. Try presenting less, more concise information, and not all at once. The initial player response to a page full of text is, "I ain't readin' all this!" It's sad, but true.
Cent Two: In the future, refrain from using anything but original characters and artwork, simply because you're limiting yourself as an artist. Even if you can't draw worth crap, an original character who's just a block with eyes is 100 times more interesting that Mario. Since everyone knows how Mario games work, that builds up some expectation in your player, but since the game acts (relatively) nothing like a Mario game, there is some visual and operational discord. When I play a game that has that completely original feel, even if it's still standard platforming mechanics, I find myself more intrigued, and thereby more willing to play.