This game is pretty good, but there are a few cons to this game :
First is the fact that shooting zombies are most likely to stay out of screen since they only move when the player is out of range...
Second is the possibility to push zombies inside the buildings with the katana, then they are out of range since you can't attack them, you just have to wait for the zombies to go through the "wall" just as if there were none...
Third is that I've unlocked all the medal (even the game says so) But I still miss 2 Newgrounds medal, the irony makes it that I've beaten the game on hard mode, but I have not beaten the game...
Fourth is when some glitch is causing the projectiles to go through some zombies...
And the last one (wich is almost nothing but still) is that bulletproof vest are made of Kevlar, cevlar does not exist...
But hey, this game was really fun still (somehow abit too short though, I had all the medals in less than an hour), and I really enjoyed the Doom reference with the BFG thing. This game has quite some potential as a time killer !