Here is the main rules document for #TvsZ. This is the official set of rules at any point in time during the game.
This slideshow explains the three game actions that will be in play throughout #TvsZ — #bite, #dodge, and #swipe.
#TvsZ also uses emergent rules that are released every few hours during the game. Those will be posted on the rules document.
Also follow @TvsZofficial for new rule releases.
Players can contribute to the creation of rules for the game by commenting on the rules document linked above. Remember though, only rules posted on the official rules document will be considered valid for game play.