Goofs

After Max talks with his dad after dinner, he is shown reading his letter to Santa. The close up shows he is reading the front page, but when the camera angle changes to over his shoulder he is reading the other side. The angle switches back and he is again reading from the front page.

While out searching for Beth, Tom helps out Howard by shooting the thing that attacks Howard 3 times with his sixshooter. Back in the house, Tom asks Howard about ammo. All Howard has left are shotgun shells. Later on, Tom uses the sixshooter again and fires 6 times. As there was no additional ammo left for this gun, he could have only fired 3 more times.

Max gets punched in his right eye at the beginning of the movie, but the developing bruise disappears halfway through the movie and never reappears.

Tom is shown by the fireplace checking the ammunition in the revolver, which seems to be loaded with large caliber cartridges like .357 Magnum. Later when he's in the attic pointing the same revolver toward the viewer, the muzzle is small in diameter as it would if it were able to fire .22 rimfire or .25 caliber.

Their house is shown on the poster with Krampus standing on top. If the den is on the bottom right where the movie ends, then why were they looking up at the ceiling of the den when the elves were running back and forth on the roof multiple times? There are 2 rooms directly above the den if we include the room with the gabled window, which could be the attic. They should not have been able to hear the footsteps that well even when the dark elves were trying to pull up Howie Jr. We even see the den ceiling collapse later when Der Klown falls through the air duct supposedly between floors no longer in the attic.

Max opens the last door on a very old and traditional looking advent calendar that appears to be a family heirloom. However the final door reads the number 25, while Austrian advent calendars traditionally only have 24 doors, as the main Christmas celebration is Christmas Eve. No Austrian advent calendar would have 25 doors.

Real-world fireplace chimneys have dampers and smoke shelves that prevent the abduction of children and preclude distraught parents' being able to look up them to the sky.

When they are trying to get to the snow plow Tom brings the shotgun with them. When that "snow monster" is chasing them he fires 13 shots at it. However a pump action shotgun with a full length magazine tube holds a maximum of nine rounds, eight in the magazine and one in the chamber.

When the power goes out, Tom is seen flipping circuit breakers on a transfer switch for a backup generator, but they don't have a backup generator. Later in the movie he asks his wife if she got him one for Christmas.

If the grandmother encountered Krampus as a child, she should be in the giant snow globe with her family, not alive with the toy that Krampus left her.

In Mucho Mart, just as the camera starts to close in through the curtain in the back of the store where the play was being held. A customer with at least a 43 inch TV box is walking from left of the screen to the right of the screen. The box was obviously empty to have been able to be held simply by the underarm as the person is doing.

At 1:06:29, a crew member in a white shirt can be seen in the bottom center/left of the screen.

Tom's plan to use the snow plow is flawed. It has been sitting with its lights on for over 24 hours by the time they get to it. The battery would of been dead by then.

The reason Krampus comes is so he can make you good for Christmas but that plan is a bit flushed. In the film Krampus kills your friends and family and leaves you alive that wouldn't make you good but would instead make you change religion and probably make you go insane.