some downsides
It has potential, but some glitches:
The barricades are pretty useless. In medium-advanced levels, monsters can destroy the strongest one in seconds.
You can survive untill the advanced levels, and then got killed in a second, witout realizing what killed you. It needs a save option, so you dont have to restart all.
Weapons are very badly balanced. Lower class weapons are better than more expensive ones. Automatic weapons are pretty useless.
Polish that, and you have a 10 game.