All melee mobs make mobs only can melee, no shoot
Artifact god mode makes shield for everyone and artifact super high, so you can't fail defend artifact mission. Also may have built in 2 hit kill so you can actually kill things, but maybe not and you will have to activate that. It gives you super high energy too which translate to extra exp at end of mission, mean exp hack.
Disadvantage, "All melee" they all stop in one spot and your sent doesnt shoot them.. so you have to hunt them down yourselves