Well...
I think this is good for a first game, but you should maybe think of, maybe making the enemies movieclips with a walking animation and stuff, else (if you dont think about the graphics) this was actually a pretty fun game!
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But, as they used to say:
If you don't play a game for sucky graphics, you're a total douchebag.
Good for first game, improve enemies a bit. Else evrything was fine!