Clark Griswold throws adult tantrums/meltdowns because of his rough/touchy personality.
Security/special police officers raid a house.
The violence is mostly meant to be funny:
A man gets punched by his wife. He falls backwards off the couch and lands on his face.
A man tumbles all the way down his stairs while holding wine glasses. The glasses are shattered.
A block of ice from the rain gutter goes flying, crashes through the neighbor's window, and destroys their stereo. We literally see sparks fly when this happens, and a man falls off the roof and into a bush. He is not harmed.
A cat is electrocuted under a chair and disintegrates into the carpet of a house. The shape of its body is seen on the carpet.
A man is gagged and brought to a house against his will. He is also kicked in the butt at one point.
A man is knocked to the ground by a ladder when he opens the attic. Then he is whacked in the face three times in a row by a wooden board. He also crashes through the attic when he is sitting on top of the door, and his wife opens it.
A man drops a cigar and an outdoor explosion knocks a big group of people down in the snow.
The police break down the doors at two different houses and have guns in their hands.
A woman is attacked by a squirrel and a dog at the same time. In the next scene, she is shown with ripped clothes, she is limping, and her face and hair are all dirty.