The Rice University Neologisms Database

Angry or upset, often due to performing something poorly. Originally used in the context of poker, tilt is a state of frustration or confusion in which the player uses a bad strategy, resulting in the player becoming aggressive. Tilt in poker context probably originated from pinball, as the frustration a pinball player would experience often led them to tilt the machine to try and move the ball towards the flippers on the pinball board.