When Meegan begins to fall down the stairs she is wearing black panties. As she lands, her panties are white.
When Debbie is cutting the lemons and talking with Anna (around the 1:06:22 time mark), the close up shot shows her wearing the pink dress with the broken strap, but one second later when she's shown fully, she's wearing a green plaid dress.
When Debbie is changing her long dress to her more modern outfit, she unhooks her bra and has the left strap off her shoulder when her neighbor walks up. While talking to him, the bra strap jumps back to her shoulder repeatedly. Finally, when she goes to take her bra off, she unhooks it again.
When Debbie is changing clothes on her way to school and her classmate approaches her, in shots from behind, her left bra strap is on her shoulder, but in front shots during their conversation, the bra strap is off her shoulder.
When Peter opens the door to Principal Joyce Saunder's office there is a plaque on the door's glass. But when he steps inside we see through the glass that the plaque is gone. In its place is the lettering "Mr. Marrow, Principal".
When paramedics transport Peter to the ambulance, he is seen with a bandage on his shoulder, where the knife went, meaning they had pulled out the weapon, which the real life EMT workers would never do since it might cause excessive bleeding.
When Peter is driving to his house to help Marlyn you can clearly see the back rim on the wheel fly off.
When her neighbor takes Rose's modern shirt you see Rose's nails are short, but when she unsnaps her bra they are long and manicured.
When Debbie removes the chef's knife from the woodblock on the kitchen counter, you hear the sound of metal against metal like a sword coming out of a metal scabbard.
After Debbie shoots the first policeman in the leg, his partner radios for backup to street address 1729. The house address, visible over the door, is 1927.