The mutant is one of the few enemies that uses a firearm. This enemy does high damage but does not have much life, better kill him with a desert eagle, some explosives or an automatic weapon ... and yes, if they can speak. They are very hostile to Bio-Bots, as they often attack them. Apparently they are mutated zombies (he says it in his own name) but the mutants do not seem to be naturally mutated, rather it seems that the scientist had apparently mutated them and mutated them to be like his personal guards, although they seem more looters than anything else (my opinion).
Like Bio-Bots, they form an army and are more intelligent than the most races inhabiting the planet: they build outposts with wooden planks to attack and defend their territory, and sometimes they hang skeletons on structures to frighten invaders. Moreover, they look to have made some kind of alliance with the scientist, as they use the Robomachine to fight the hero. However, it could also be assumed that mutants have secretely reprogrammed the machine for killing, since the scientist, after the player has destroyed the robot, looks to be surprised by his behavior, as if he didn't knew that his invention had just tried to kill the hero.