War Robots - Extermination Stage 4 After Titan Charge Nerf (Rocket Weapons Deal More Damage) 

For Stage 4.1, you can actually stay on the steps of the Colosseum and receive less damage. For Stage 4.2, instead of using Argon/Cinders, you can use Argon/Oxy on the Luchador, it is a lot easier to kill the big spiders.