"Dead in a minute": A fun, fast, and frustrating multiplayer setup

This is how I usually play Xonotic
-Deathmatch
-Mutators: HLAC weapon arena or InstaGib
-1 minute time limit
-Unlimited frags
-Map: Warfare
-8 players recommended
have fun

Just so you know, Minstagib = Mutator Instagib and Instagib is just plain normal instagib. I don't know the differences about the two.

There's no difference, mutator refers to a game mode that has settings that "mutate" the regular gameplay. In general things like low gravity, infinite ammo, instagib, weapon arena.. etc. The "mutator" addition in Instagib is not necessary, because Instagib by itself is already a mutator. Instagib is the proper term for Instagib.

The truth is indeed the truth!