Great idea...execution need some work!
Take it from me- I'm a pretty big fan of pixel-based games, especially if they remind me of Pitfall, Mario, Contra...stuff like that. So your game is quite beautiful: simple design, simple mechanics. It's a quick and enjoyable game to get into, which is the beauty with many (but not all) Newgrounds submissions.
However, there was one point in the game where I was stuck...it was shortly after beating the first boss: a room with three platforms, and the center one disappears. I'm not the greatest at video games (insofar as beating them goes)- but holy crap was making that jump difficult, or next to impossible. This is just a frustrating part of the game, where you know you can jump- but this specific jump requires precise timing and control of your character...when you're dealing with this simplistic of a game with those controls, you can't really press people into that unless you make use of your simplicity.
Overall, badass submission. I look forward to more.