Just a bit rediculous.
I've killed over 2,500 zombies and I'm only on wave 14 of 20. 20 waves????? you got to be freaking kidding me. It is so tedious that I would be surprised if anybody ever finished this game. Besides, how many freaking people were in this prison anyway? You would think that with 2500 people around somebody would have objected to the experiments that caused this problem.
Other than that the game is ok. It was fun in the first level but then it just became this huge chore. I'm going to try to finish but it seems almost pointless now.