The Walking Dead is one of the hottest TV shows right now and while there has been many theories about the show, the most popular being the whole thing is Rick dreaming in his coma. But I have thought of one that will make gamers happy. The whole thing is one huge virtual reality game. So pretty much the theory goes like this.
By wearing laying down on a bed like in the movie Avatar they let people take control of a avatar that looks exactly like themselves. Then you find other online players trying to survive, and when you die you get kicked from the game but your avatar stays behind and reanimates. Players can only rejoin after the server (which is based on the country you live in) restarts (when everyone on the server dies). Also just like Avatar when you go to sleep you leave the game and when you lay back in the bed you wake back up in the game.