In the Robo Rumble Event, three players battle against many waves of robot enemies to protect a safe. The first wave starts immediately and each wave lasts 13 seconds after that. There are four types of robot, a "melee robot" with high health and fast attacking speed but low range, a "shooter robot" with low health, slow shooting speed but high range, a "mini robot" with low hitpoints, medium attacking speed but high movement speed, and a "boss robot" with very high hitpoints and damage. The boss robot has a melee attack or can shoot rockets, and one arrives every 7 waves. After a boss robot arrives, all robots after that have increased health and damage. Robo Rumble is an unranked mode, so Trophies cannot be earned or lost.
- Barley and Dynamike: These "throwers" can take out swarms of robots behind the cover of a wall.
- Pam and Poco: These healers can help keep their teammates alive to avoid the slow respawn delay present in this game mode.
- Ricochet and Colt: Ricochet can stay from behind and use his bounce shots to his advantage to hurt Sniper Bots without taking damage, while Colt can attack the Melee and Mini Bots from a far range.
- Respawn time is 10 seconds instead of the normal 5, so it is important to stay alive.
- Don't be separated from your team. Try to stay close and destroy as much robots as you can.
- During Boss Rounds, if you are having trouble taking out the Boss, try to kite it around the map instead of leaving it near the safe. Great kiters are Brawlers with long range, such as Colt or Ricochet.