When a player clicks the Berserk button at the beginning of the game, they lose half of their clock time, but the win is worth one extra tournament point.
Going Berserk in time controls with an increment also cancels the increment. (1+2 is an exception, it gives 1+0)
Berserk is not available for games with zero initial time (0+1, 0+2).
Berserk only grants an extra point if you play at least 7 moves in the game.