Other mistake: Mara wore a light - (white or pale pink?) colored gown to the prom. Dylan's relatively "fresh" grave is still a mound of dirt with some leaves/debris scattered on it. Despite lying on his grave for some time (overnight), Mara's gown does not get wrinkled or soiled; her gown looks totally clean, dry, and wrinkle-free when she gets home. (01:23:30 - 01:29:20)
Other mistake: Near the end of the movie when Mara is driving away in Dylan's milk truck, she looks into the driver's side mirror and sees a perfect image of her parents standing in the driveway. Considering her parents were standing on the passenger side of the milk truck before she pulled out and given that she is driving away from a cul-de-sac, Mara could not possibly be able to see her parents in her mirror as shown. (01:32:30)
Other mistake: The way Katelyn exploded was described by Mara as being like a balloon popping. Every time a student exploded, blobs of blood (and tiny pieces of the body) splattered everywhere, making a huge bloody mess. When more than one student exploded going down the stairs, blood looked like it was being poured from a bucket. Sometimes, parts of clothing could be saturated in blood (such as a sleeve), but there was always more blood splattered nearby. When Katelyn was at the doctor's office (to get a piece of someone's bone removed from her forehead), "blood" goes smoothly/evenly around her eye to the lashes with no gaps or splatter marks. Blood from an explosion would not fall this "perfectly" around eyes. For example, folds in the eyelids would block some blood from landing in certain places and eyelashes should have some blood on them but Mara's did not. (01:41:27)
Other mistake: Rain doesn't seem to land on the main characters - it's raining in the background behind both Mara/Tess and Joe/Jenna while buying the mushrooms. Also, when Mara and Dylan are sitting on the curbside by the car, it's raining on the car but not them.
Continuity mistake: After Dylan explodes, we see Mara with a white bandage on her forehead. The bandage switches from left to right and then back to the left (and possibly changes size, but I am not too sure about that).
