PES 2012's gameplay is primarily a refinement of PES 2011, with many improvements and changes in areas such as artificial intelligence, speed, animation, and physics.[9] Among the new features is the Teammate Control system, where a secondary player may be controlled, either during play, or at a set piece or throw-in. This allows players to be placed precisely, make runs, and shake off markers before calling for the ball. Manual and assisted versions of the feature are available for varying degrees of difficulty and control.[10] Refereeing has been improved and includes a full implementation of the advantage rule, with the referee pulling back play for bookings after the ball goes out of play.[11] The "catch-up bug", where defenders would catch dribbling attackers too easily, regardless of the attacker's pace, will be addressed.[11] Gameplay is more fluid, with better response when controlling the ball,[11] and goalkeepers have been improved with new animations and generally more reliable goalkeeping performances.[11] Artificial intelligence has been improved over previous PES games, for example AI players will play more thoughtfully when defending rather than simply applying pressure, and AI teammates will make more intelligent movement decisions.[9]