There's a scene where an 11 year old girl saves Kick-Ass by killing many people in an apartment. This scene is very bloody and brutal.
There's a scene where a man is in a microwave and he blows up. Blood and guts go all over the screen but it's done in a comedic way.
We see a man in a car that's positioned in a car crusher being controlled by Damon and Mindy. She then activates it and the device slowly starts to crush the car and the man (we see a brief burst of blood onto the windows during this).
We see recorded video of a superhero's attack on a criminal lumber factory and him killing the heavily armed men there waiting to ambush the superhero (the latter never happens). During that, the hero hits, shoots, stabs and slices many men (with various weapons and with bloody results). He also uses a grenade and then sets fire to the factory building.
We see the protagonists stuck to a chair, they get beaten with metal plates, pipes, bats and batons through the groin, head and the body while the news and most of the internet watch both of them get beaten, (Very Brutal)
A young superhero girl about 11 proceeds to shoot many heavily armed men (handguns, shotguns, machine guns, etc.), killing all of them (with bloody results).
The teen stabbed in the stomach by a knife and after that a guy hits and runs him making more pain, there is blood and pain, got hospitalized.
One of a bosses men is accused of selling coke to some Russians and then taking the money. He claims he's innocent, but no one believes him, and another goon holds a bolt cutter around one of his fingers. We then hear that snip and scream, but don't see the actual cut.
A father holds a handgun on his daughter, calming explaining what's going to occur and asking her questions, etc. He then shoots her, knocking her off her feet, but we then see she's wearing a bulletproof vest. There's a comment that two more practice shots are coming, but we only hear one of them (and don't see the impact).
Knowing he no longer has any pain receptors, a teenage boy and another repeatedly hit and smash him with things in the cafeteria to test that.
Seeing a superhero walking down the street, A bad guy has his driver follow him into an alley. The man then gets out, kicks the superhero to the street and then punches and kicks him quite hard. When a bystander passes by, the guy shoots that man in the back twice, and then shoots the superhero in the head (we later learn this was an impersonator).
A teenage superhero and another one arrive at a man's lumber factory that's now fully ablaze (and one of them is blown backwards by a fiery explosion when he opens a door) and they find several dead and bloody men inside, one whose throat has been slit (with bloody results).
A person dresses as a superhero and surprises his girlfriend in her room. Rather than be excited, however, she goes on the attack, first spraying something into his eyes and then hitting him repeatedly with a tennis racket.
One teenager lies to his superhero friend about being in trouble and them needing a superhero and another's help (all to set up an ambush of the latter two). When they arrive at the superhero safe house, The teen shoots the littler girl out the window, while goons arrive and shock the father into submission while grabbing the superhero and they put them in the van holding them captive.
The lights go out and Mindy starts her attack, flitting about while shooting the goons one by one. During this, however, one ignites the kerosene below Damon and the flames grow from his feet and then up his body as Mindy races to kill everyone so she can rescue her dad. When she's done, she shoots the camera broadcasting all of that.
A little girl pretends to be a lost little girl to make some of a man's goons drop their guard. She then has her gun inside one man's mouth and shoots through that to kill another. She then shoots everyone dead in the building lobby, with varying degrees of bloody results.
The superhero girl continues her attack, this time with a knife or some sort of blade attached to a rope or cable that she flicks out to stab, slice and otherwise kill many men, including using that rope to cause one man to shoot himself (with bloody results).
After Mindy has run out of ammo and hides in a large kitchen, one goon riddles the place with machine gun fire, but doesn't hit her, while she manages to fling two large kitchen knives into one man's chest, killing him.
In a flashback, a teenage boy's mom's head suddenly hits the kitchen table, with her dead from an aneurysm there is no blood. (played for laughs).
A man tied into a chair being interrogated. An attack occurs and one of the masked men uses a lighter to activate the gasoline, one kid avoids the fire but it spreads on another. He is burned but it isn't seen but we do hear the screaming of pain before his death.
A teen appears outside a high-rise apartment building hovering with a jetpack that has two Gatling guns attached; he opens fire while moving horizontally, breaking many windows and shooting a few men.
Several men chase another man, they catch him and they punch and kick him several times (his head and face is a little bloody); a teen boy joins the fight, kicking and punching and the attackers start punching and kicking him; one man draws a knife and threatens the teen but they are interrupted by the sound of sirens.
Many men are seen dead inside a flaming building. One has a slit throat and shot body, decent amount of blood. The superheroes get out just before the criminal warehouse explodes.
We briefly see the full body X-ray of a teen boy that shows many metal rod implants and screws used to repair numerous broken bones.
Whilst it is extremely violent, it has a comedic effect by the violence being unreal.
The ending scene, where the two main heroes are fighting with the villains shows Hit-Girl stabbing a few armed men.