Goofs

When Fool and Leroy first encounter Prince, they secure him in the room beside the kitchen, with the door to the outside closed. Yet when Mummy and Daddy return, the dog somehow has managed to get out of the super-secure house to greet them.

When Fool falls down the basement stairs, at the top of the stairs he has on one shirt, when he gets to the middle of the stairs, he has on another shirt, and when he finally lands at the bottom, he has on the first shirt again.

When Daddy gets tricked by the coins pushed into the candlesticks, it shows the same coin falling from the same candlestick twice.

When Alice is telling Fool about the boys downstairs in the bathroom, she begins to cry and tears stream down her face. In the next shot the tears are gone and it doesn't look like she was crying at all.

When the man blasts away the trap door in the wall, pieces of the door are left in place. But when he walks up to the wall to yell at Roach, the area surrounding the hole in the wall is perfectly square as if the door was never there.

When fool goes to the payphone to call the police, the rotary payphone required coins for its 9-1-1. The real life payphones in L.A. were touch-tone that have dial tone first (no coins needed for 0-perator, 911, toll free and credit card calls. The LAPD have uniforms that say Los Angeles Police Dept. in silver crosses, not yellow insignias.

Leroy (Ving Rhames) tells Fool, "you're being evicted. You gotta be out tomorrow. California law (the movie was filmed in Los Angeles) requires 30 day notice for eviction.

When the Mother/Sister is trying to escape the house out of the window, to get away from the People Under the Stairs, one of the PUtS, breaks through the wall under the window to grab her by the feet, despite the fact that the wall is an outside wall, and not thick enough to have a space big enough to allow a person to be inside of it.

When Fool hits Daddy with the "iron" poker, it snaps in half and is obviously made of thin wood. Fool stops briefly, and looks off set in surprise, before continuing with the scene.

Alice's kneepads are visible when she's cleaning up the blood.

When Leroy is being attacked by the dog behind the couch, one shot clearly shows the dog to be a stuffed animal.

Kneepads visible on Alice when she falls from the ceiling and attack the Woman.

When fool slides down the steps a second time, you can obviously see it is a shot from earlier in the movie, where he is wearing a red striped sweater. However, that day in the movie, he is wearing a bright green vest, with no red sweater.

When they discover the dog is dead, the Woman says "Oh My God, Prince!" but her mouth doesn't.

When Alice and Fool are going through the walls when she whispers "Shh, if he can't hear us, he can't shoot us." Her mouth did not move at all.

As Fool is attacked by Prince he says "Alice, just go!" but his mouth doesn't.

When the Man and Woman return home, the Man locks the door behind him. Three distinct clicks can be heard, but there is clearly only one lock.

When the police car pulls up to enquire about the van, in a side shot of the car you can see a crew member reflected in the back window.

Why is it possible for the people under the stairs to bust through the walls and stairs but not through the wood slats that keeps them in downstairs? Especially after the boards have been weakened by gunshots.