Continuity mistake: Kerry's hand is severely burned from the acid, but in all following scenes her hand shows no burns. (00:16:00)
Suggested correction: They do show burns throughout the rest of the scene.
Revealing mistake: When Kerry is in the Angel trap there is a close up of her about to put her hand in the acid for the first time before it changes to a spinning shot. In the close up, watch very closely and you will see her fingertips enter the acid but she doesn't get burned or scream in pain. (00:15:40)
Revealing mistake: After Jeff shoots Amanda she falls to the ground. You can tell it is a dummy, just watch her arms and head.
Suggested correction: First of all, she doesn't fall to the ground. She stumbles after being shot and then slowly collapses to a seated position. There is also no dummy being used, as Shawnee Smith's face is visible in every shot of her until she dies.
