Goofs

When Lomax is making holes in clothes with his cigar, the amount of holes, his position and position of the clothes is not synchronized between shots.

When the men are waiting in the room, the lighting discontinuity is obvious, with Billy next to the window being in the dark, but when the close-up of him is shown, there is light on him.

When wig and clothes are thrown on Lomax, they are in different position on him in the next shot.

When Lomax enters the house, position of the dead chicken is changed from the one seen in the shot when Lisa puts it there.

Some scenes in the movie are obviously filmed by a cameraman walking around. Even the edge of the screen can be seen in the corner, and in the scene where criminals chase a man running from the house even his steps can be heard.

When Lisa wants to cut her wrists, her breath and sighs can be heard even before her mouth is open.

Lomax obviously breathing after being killed.

Criminals make a mess in a store and humiliate the cashier, but it wouldn't make sense because they are trying to lay low after a murder and that would only give police a trail to follow.

Lisa kills Lomax by cutting the back of his neck. While doing that is obviously harmful and can cause great injury, there is a reason why the front side of the neck is attacked as shown in countless movies because slicing a throat can cause a quicker fatal injury. It's highly doubtful Lomax wouldn't react to the attack in some way and overpower Lisa due to the wound not being fatal.

Lisa makes Billy carry Lomax's body parts to the attic in a trunk. There is no way he would have enough strength to carry a trunk containing a whole adult man in it up the stairs as seen in that scene.

When girl is bringing dead chicken in to the house, a head of a man with glasses can be seen just above the stump.

In the shot of the girl and grandpa right before the criminals arrive, a shadow of a man can be seen moving on a wall and it's also heard somebody is walking around, probably a crew member.