Visible crew/equipment: When Fool and Alice are sliding down the chimney after Fool hits Daddy with the brick, you can see the cable supporting the two as they descend. (01:17:40)
Continuity mistake: When the Man and Woman have lost Alice, they look in the kitchen to find her, and the Woman starts opening up some cabinets and in the process she leaves some of the doors open. Then in the next shot, the cabinet doors that are open have now changed, and some doors that were open in the previous shot are now closed. (01:20:20)
Revealing mistake: When Alice bursts out of the ceiling and knocks the Woman out, her kneepads are visible. (01:23:40)
Visible crew/equipment: When Alice bursts out of the ceiling and knocks out the Woman, as she descends from the top, you can see a white guide wire attached to her. (01:23:40)
Continuity mistake: In the very beginning, Fool falls down the basement stairs when the man pulls the lever to make the stairs a ramp. He is wearing a purple and black striped shirt. Later, near the end, Fool goes back into the basement on the same stairs. This time, he is wearing a green shirt. When the man chases him and pulls the lever again, we see the same footage of Fool rolling down the stairs/ramp from earlier (black & purple shirt). When Fool gets back on his feet, his shirt is green again. (01:24:15)
Revealing mistake: When Alice trips and falls on the staircase, the Woman gets on top of her and tries to stab her. Throughout their struggle, you can clearly see that Alice is in fact replaced by a stuntman. (01:28:00)
Revealing mistake: When the Woman is trying to attack Alice with the huge butchers knife, in one shot you can see it bend and wobble a little bit, revealing that it was fake and rubber. (01:28:10)
Continuity mistake: When the third Person from Under the Stairs bursts out (from the wall) the Woman is flinching in the corner, pressing up against the wall. As she does she breaks the brown wooden panel in the wall behind her, splitting it in two. In the next shot the wall is back intact. (01:28:45)
Continuity mistake: When one of the People from Under the Stairs bursts through the wall, trying to attack the Woman, the hole it makes in the wall has wood splinters hanging all around it, yet in the next shot it is completely free of any splinters and looks much more neater. (01:28:45)
Revealing mistake: When the Woman is attacked by the People from under the Stairs, it quite clear that it is in actual fact a stunt double. (01:28:50)
Revealing mistake: After Alice stabs the mother with the knife, the mother begins to take it out. However, you can see that she's taking it out from the side of her body and you can even see the point of the knife on the other side. (01:29:05)
Continuity mistake: When all of the People from Under the Stairs attack the Woman in the kitchen (as she tries to stab Alice) one of the people climbs out of one of the cabinets twice between shots. (01:29:55)
Continuity mistake: When the Man gets tricked by the coins pushed into the candlesticks, it shows the same coin falling from the same candlestick twice. (01:31:35)
Plot hole: 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. (01:32:00)
Continuity mistake: After Fool sets off the explosion sending the money out the chimney, there are about five minutes of different scenes, and then we see the chimney a little later, and it's still sending money. (01:36:35 - 01:38:15)
Revealing mistake: When the man pushes Leroy's body down the basement stairs, as his body is sliding down, when it's almost to the bottom, you can plainly see Leroy lift his head up as he's sliding, although he's dead.
Continuity mistake: When Fool walks down the stairs, he picks up Spencer's lighter and pad, then gets scared and runs back upstairs. As he runs, between shots the items he holds swaps hands.
Continuity mistake: The small hole in Fool's tee-shirt, just under the collar, keeps changing appearance throughout the movie, and sometime it even disappears in scenes, then is there in other scenes.
Continuity mistake: When Fool walks into his apartment building in the beginning, he is walking up a flight of stairs...but while in his apartment you can see grass and the ground right outside the window.
