Positives:
I love the idea - it reminds me of a game I used to play in primary school, but it's just different enough to not feel like a rip-off.
The artwork, in my opinion, is rather charming. Sort-of between Atari & NES. I like!

Negatives:
Game feels like it could have a little extra something. Not sure what.
Could be just me, but if you run out of ammo, the baddies decimate you if another weapon doesn't drop.

Overall, 4/5 stars - Solid.