excelent game!
I only ran into one bug, which was that the chainsaw sound kept going on after I had switched out kinda fast, I dunno what happened, but it didn't happen again.
since most of the other reviews cover the good pointsof the game, I'll give my hints & Tips.
no matter what weapon you have out, have your secondary be chainsaw. it literally cuts through anything at the wall, and using the mouse and movement keyes can easily defeat any horde at the wall.
for the most part, headshots are the best go for. the only trouble is when the zombie soldiers come, so when that happens, aim for their FEET. no armor or helmets there, and they fall over, dead. very useful as the barret kills everything EXCEPT army men in one hit, so just aim for the feet.
the only improvements I can see is perhaps more variety of weapons, longer gameplay, and perhaps more to do.
oh, and more people. or at least, manage it better. because you can only have 7 total, but it's not that clear the first time I went through, and you can keep searching for people and weapons when you have the max...
maybe if the army didn't come, you had to move and make new barricades in different places, with more scenery and obstacles.
A sequel would be nice :D
~Qwerty