I don't understand why I'm addicted. I have never understood the zombie fascination and honestly, I think it's beyond stupid. Every time I hear people mention something about zombies I roll my eyes and think how foolish it is. I got the game from Amazon because it was free and I can't pass up anything free. I started playing it and am incredibly addicted. I've beat the entire game and I'm in the middle of playing it through a second time. I've also unlocked a ton of stuff and played the quick play modes several times. I've unlocked several achievements. I'm addicted to the stupid game and I have no idea why.