From the BBC:
It uses high-speed recognition and reaction, rather than prediction.
Technically, the robot cheats because it reacts extremely quickly to what the human hand is doing rather than making a premeditated simultaneous action as the rules state.
Taking just one millisecond (ms) – a thousandth of a second – to recognise what shape the human hand is making, it then chooses a winning move and reacts at high speed.
Version one completed its shape 20ms after the human hand; version two finishes almost simultaneously.