WWE '13 runs on the engine called, "Predator Technology 2.0", which succeeds the first version from WWE '12. The Predator Technology 1.0 game engine has been updated from the previous WWE games to allow for more fluid animations, with odd collisions and transitions having been fixed and updated, it also allows over 300 new moves. Past problems have been fixed with a better weight detection system, contextual animations and automatic attack homing, to ensure that the character always strikes towards the opponent(s). The contextual animation system has been refined to ensure that it dynamically swaps out moves to make sure that the game is using the appropriate move animations at any given time and state. The weight detection system makes it so that small superstars such as Rey Mysterio are unable to lift larger wrestlers such as the Big Show. Thus, the contextual animations ensure that more appropriate attacks are put in the superstar's normal moveset. The game's new homing system is designed that when doing high flying moves, a player will hit the intended target with better precision. The homing system also tracks tables so that they will be better detected when doing grapples on a ladder in TLC and Ladder matches. This feature allows for environmental moves such as ring breaks, barricade breaks, announce table breaks, and catching (mid-air) finishers to be possible. Another new feature is a different model for the giants in the game. Previously, a single body structure was used for all superstars. THQ has also claimed that the game has the most life like superstars. Another important aspect of the game is the new revamped audio system with remastered sound effects. The crowd reactions and commentary audio has directly been taken from live WWE events. Online servers have been enhanced to allow for players to test out creations before downloading them into the game. The "Special Referee" game mode has been added in since its last iteration on WWE SmackDown vs. Raw 2007. During online matches, AI will fill in for absent players when not enough players are available.