I've been playing solo and I don't find it fun at all. There are 2 choices and both are boring and ultimately don't satisfy what I'd expect from a survival zombie game. 1) City play is nothing more than an arena game. Rush to get a good gun and hold a building. Fast deaths and ultimately boring because there is no interaction with anyone seems how everyone will shoot you on site. 2) Rural play, small towns, deer stands, and lots of running with hoping and preying that you find some matches before you starve. I think this is more fun seems how you are less likely to be gunned down within the first 20 min, but it gets frustrating seems how LOTS of the buildings out of major towns are inaccessible. Overall, once you figure out how to pull the zombies inside and run out the other side and how to lose them through trees or kill them easily with a hatchet the game gets boring solo because people are just out to kill each other and its nothing more than a 1v1v1 death match game. People are more afraid of people than zombies and there is no reason to work together because the zombies are retarded. Basically - bad pathing, bad sight when running through trees (run into a pine tree, then crouch and keep moving [they will take 1-2 seconds to reset line of sight], prone after 1-2 seconds of being crouched and crawl away), walk up hills, walk indoors, now zombies climb so you can just sit at the top and hatchet them one by one, bad change because it's harder to have to come back down to 5 zombies than kill them one by one).
