Good
It needs a "continue" button. What I mean is, when you pass the level, you could later continue from the next level. I would like to complete the game, but I don't want to go through everything again after I die.
Next thing is a real highscore table. If you got one you could make 2 modes for a game. First one would be like a story mode, where you can complete the game, and then there could be a challenge mode, where the enemies are endless, untill you die and submmit the highscore.
Other than that, it's cool, I like killing nazies. :D