Needs a lot of improvement.
Well, it seems like you're just starting out in actionscript. You got Bill's basic movement down, but your main flaws come in with shooting. In the contra series, Bill can fire at almost any position imaginable. In this 'game' he can't even fire while running, not to mention the fact that he fires at about 1 bullet per second.
It also looks like Bill's bullets are a part of the same movie clip as him, so whenever they hit another platform, it propels him backwards. I'm sure if you looked up some tutorials you could find an easy way to fix a lot of these problems.
The main problem, however is the fact that you're submitting a completely unfinished game. 3 Platforms and a player does not a game make. Also, your platforms were simply black boxes. You couldn't use some sprite from contra for your platforms or even implement some sort of decent looking background? Take it from me, submitting an unfinished game is not the way to go in terms of Newgrounds.
I hope my review helped you in some way, good luck in the world of actionscript.