Realism does not define this game, the rule of cool does. However, that doesn't mean that realism has no place here. Weapons have weight and must be wielded with the intent to kill if you don't want to meet your demise. Firearms require precise aim to fit the bullet between enemy armor plates... Or just buy a weapon with a caliber that will go through anyone and anything that dares stand in its way, the choice is yours.
Everything is simulated physically, throwing your enemies through windows and off roofs, launching a stake through their torso and pinning them against the wall, slicing their body in half with a blade that's more of a large hunk of iron than a sword, and even climbing and using grappling hooks. Dismemberment is not limited to limbs or even joints, splitting someone's head in half vertically is not a question of if but rather when.
