Destroy 40 units with a single unit in an Unranked or Ranked game.
Kill 50 supply worth of units within 15 seconds in a Melee game.
Attack for 20 seconds with no counterattacks in an Unranked or Ranked game.
Score the rank of Gold in all the challenge missions.
Survive 15 Infested Horde Attacks in the “Night 2 Die" mode of the “Left 2 Die” scenario.