When Mother Russia tears off the car door and uses it as a shield, she then throws the door at another police officer and there are no bullet holes/dents visible.
When Hit Girl answers the phone to talk to Marcus, her headset's microphone is on the left side. After she parks her bike and tosses her helmet, the headset's microphone is on the right side.
When Kick-Ass and Night Bitch stand on the street, her lips are purple. Next scene in the bathroom, they change color to pink.
During the fight between Hit Girl and Mother Russia, the bullet-time scene depicts Hit Girl stabbing Mother Russia in the chest with two glass shards, but in the next scene there's only one.
When Mindy shoots Dave while training, there are two bullet holes in his jacket when he has only been shot once.
When the lawn mower crashes through the police car's windshield, the windshield breaks into long shards. Windshields are made of two glass sheets sandwiching a plastic inner lining and do not shatter like regular glass.
When Mother Russia blows up the first police car, the powerful blast flings the vehicle high upwards, yet the tree right next to this event doesn't even sway in a breeze. In reality, even a small explosion will set off a shock wave that's visible for quite some distance.
At Dave's father's funeral, Dr. Gravity tells him the team would love to help but can't because they "just got out on parole."
This is inaccurate because parole refers to early release from prison following a conviction. Although the Justice Forever members were arrested, held and released, they were never formally charged or convicted of any crime.
This is inaccurate because parole refers to early release from prison following a conviction. Although the Justice Forever members were arrested, held and released, they were never formally charged or convicted of any crime.
The adrenaline should be kept in an ampoule or a specific injectable pen and not in a syringe with a needle already fitted simply to avoid getting it contaminated and also losing its chemical properties.
As Hit Girl races through a park on her motorcycle to get home before Marcus, you can see the tracks in the grass from previous takes.
When Mother Russia destroys the police cars, she puts a lawn mower on the trunk of one and then backs that car into another one, which launches the lawn mower into the windshield of the police car. That model lawn mower needs to have the control handle held down, otherwise the motor turns off.
Obvious CG green screen during the van gun fight.
The explosion could not have triggered such a jump up in the air from the police car and, similarly, could not produce as much force to project the policemen to the sides without burning them -- but this could have been played for laughs.
Outside the high school at the beginning of the movie, Dave runs up to Mindy and says, "Hey," clearly without breathing heavily. Dave was clearly catching his breath after he stopped running.
Mindy and Dave speak about their secret identities while in the taxi, revealing it to its driver, a perfect stranger.
In Kick-Ass (2010), Mindy says she promised her father to finish up their mission to stop D'Amico, not to protect the city as she now states.