Entertaining, but a bit too easy
I think this game is fairly good, and it's obvious a lot of work went into it, however it was way too easy. I found that by speed tapping the spacebar to continuously switch weapons, rate of fire was artificially boosted, making it easy to take out all enemies on all levels, mostly before they even reached the barricades. You get a good grade for the graphics and atmosphere, but for a better grade, harder gameplay is needed.