Settings: Max win = 1. Launch a game with yourself alone (without bot or friend), in the following maps:
Map Factory -> go under the roller to suicide -> π LIKE A WORM
Map Lifter -> Hold LMB under the lifter, to get off your left arm, then RMB for the right arm. Go under the lifter to suicide. (maybe 2-3 tries required) -> π NO ARMS
Map Axes -> jump to let the flying axe to cut your legs and suicide. (maybe 2-3 tries required) -> π NO LEGS
Last, play with a friend or a bot (if with a bot, preferably in the 1st map). Just knockout your opponent by clicking or holding LMB/RMB to lower enemy HP to zero -> π FIRST DECAPITATION