I have been looking for a game for the Xbox 360 which is similar to what you're suggesting, but there wasn't any, so people recommended me to check out DayZ. I checked out a couple of the gameplay videos on YouTube and realized that the zombies moved at a fast pace, which was pretty upsetting. The ability to choose the speed and amount of zombies would be great, especially for fans of The Walking Dead TV series. I understand that DayZ is based around the movie '28 Days Later', but giving us the ability to choose our own options would be highly appreciated. I realize that this thread was created in April, so I'm a little bit late on the discussion, but I read the pinned thread within the suggestions section and I was notified to contribute to an existing thread, rather than to create a new one; so here I am!