There was already other threads, but let me reiterate:
This game is terrible.
I went on the forums and posted my opinion on how their game designing skills suck stuff, with a well-rounded and thought out argument, and got IP banned. The ban reason/excuse was that I called them out on their stuff game design to make myself feel better. Anyway, to summarize it:
-Networking sucks. Zombies are clientside, but they try to make it seems serverside (watch your teammates fire at nothing :O)
-Extreme lag. There's virtually no optimization, and simply having a large number of players or enemies on the screen at one time drops your FPS to a crawl. (large being more than 4-6)
-stuff tons of useless classes. There's literally like 5 of the same class, with different names and different amounts of money.
-The town GUI or whatever the forget it is was confusing my first time playing. Probably because it looks like spilled brown paint.
What's so bad about the whole ordeal is that they actually have a ban reason for that, inferring that it's a common occurrence.