The whole world becomes more real and interactive. You can kick severed limbs and heads (and sometimes, use it to activate some traps in the map earlier, or even kick them against enemies to do some damage), you can shoot enemies' heads to deal more damage (and cause more gruesome deaths) you can destroy most things in the the scenario (trees, lamps, hanging bodies, etc), you can paint the floor, the walls, and even the ceiling with blood, you can push the explosive barrels to make traps, or grab them and use like an explosive weapon, you can silently take down enemies from behind and perform stealth kills, the chainsaw actually cuts the enemies in two. When you find the berserk pack and get super strength, you can perform cinematic executions and RIP AND TEAR your foes with your bare hands. Some enemies will scream in anguish and try to crawl away when near death, and they can be used as human shields, and much, much more.