Ok, so at the beginning I thought "ok, you collect ammo, it's not everything", but then! You can use pieces of the bugs! And zombie heads! Hell yeah!
The presentation is ok. I can see what's happening, but not amazing. Usual game-jam level I'd say.
The fun factor? I'd say it was ok, BUT then my son played it, and he loved it! So yeah, extra points for you here :)
Over all- keep it up!