When the dominoes are falling around the doll-house, the second last shot clearly shows the left leg of dominoes leading to the door has stalled and is no longer falling while the right leg continues, however in the next shot, the last few dominoes that lead to the door are clearly falling from both sides instead of just the right.
Right after walking knee deep in water in the Mirror Room, Cathy's (Judith Ivey) dress is dry in subsequent scenes.
In the beginning of the film, Steve states that Rose Red will be torn down on July 1st. At the end of the film, as the survivors stand outside Rose Red, it says "6 months later". However, the expedition took place Memorial Day weekend, at the end of May. If construction was postponed, 6 months later would put the date at the end of November or the beginning of December. Therefore, in Washington State, the characters should be wearing winter gear, not summer-type clothes.
Steve says he's going to check the kitchen door, and starts running off. Rachel follows and says she'll go with him. Joyce then yells "Steve!" and he turns too look at her and says "Not now, Dee". Her name is Joyce Reardon, and we never hear any mention before this of her being called Dee for any reason, so it seems the actor mistakenly called her Dee and they just ran with it to save time.