Character mistake: The officer misspells Mara's surname as Caryle rather than Carlyle when he writes "not helpful". (00:02:55)
Character mistake: They keep calling the vehicle a milk truck but it says "ice cream" on it. (00:23:55)
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).
Continuity mistake: The amount of Mara's cocktail [called "All of My Friends and Boyfriend Are Dead"] in the martini glass changes. She initially adds grenadine to almost the rim, but when she raises the glass, it is not as full. There also appears to be somewhat more in the glass when she sets it on the table for her dad. (01:07:50)
Continuity mistake: When Joe Dalton is driving Jenna and Mara to pick up the drugs, a few yellowish-white flowers are dangling in front of him, but seem too far to the left (toward the driver) to be hanging from the rearview mirror. However, views from the back of the car to the front do not show any flowers. After Joe "explodes" and Jenna is trying to get into the driver's seat, there is something hanging from the rearview mirror (possibly a pine tree-shaped air freshener) that was not previously there. (00:31:39 - 00:32:25)
Continuity mistake: At the restaurant, the chairs at the counter behind Mara and Tess get turned sideways a few times even though no-one is moving them. (00:08:36 - 00:09:19)
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.
Other mistake: After Katelyn "exploded", the school was evacuated and Tessa met Mara in the parking lot. Tessa was not in Mara's third period pre-calculus class, so asked Mara what happened. The entire pre-calculus class was taken to the police station for questioning. Tessa [or someone who looks just like her!] appears to be standing in the corner wearing a gray sweatsuit like the others. Tessa was also with Mara to be interviewed by Special Agent Rosetti - but Tessa was not in the class or a witness. (00:03:26)
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: It obviously rained during Mara's 10-mile overnight walk to Tessa's house (the road in front of Tessa's house was wet), but Mara (clothes, shoes, etc.) was dry. Mara somehow miraculously and totally avoided getting wet (or even splashed) while walking long distance, unprotected in the rain! (Carrying a bottle of alcohol and drinking heavily did not affect her ability to keep her shoes from getting muddy). (01:09:00 - 01:09:26)
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)
Continuity mistake: At the prom, Mara "spikes" the punch with a clear alcohol (tequila or vodka?) and the punch looks clear or a little cloudy/white. The punch is a pinkish color when Mara takes the bowl away and sits down. (01:19:45)
Other mistake: Near the car crash site, Dylan is looking toward a large rock or Boulder that has a handprint made out of blood on it and apparently uses this as an indicator of what direction Mara went and then looks for her. However, Dylan could not possibly see the bloody handprint from where he was standing - the handprint is on the opposite side of the rock (visible to viewers). (00:33:14)
Other mistake: Mara has white shoe laces in her navy or black Converse high-tops. After the car crash and Mara gets out of the water, her shoe strings are dyed pink. Mara's white top has turned pink or magenta, supposedly from the blood getting diluted when she was trying to wash it off in the water. The shoe laces may give the impression that they, too, turned pink from diluted blood, but the pink or magenta color is not how diluted blood would look. Besides, the white soles and toe tips stay white. (00:31:00 - 00:34:12)
Other mistake: When Mara and Dylan are placed in isolation, there does not appear to be a plastic barrier between their beds (but one is visible a little later). Mara and Dylan's index fingers look like they are almost touching when Mara says "ET" and Dylan replies "Elliott", but the next view - from the front of both - their hands look about a foot or so apart and the plastic barrier is in place. (00:36:14 - 00:37:33)
Revealing mistake: In the car (and while it was raining), Jenna put on her sunglasses a little before Joe "exploded", suggesting she was preparing for the blood splattering. [Interestingly, Jenna put on the windshield wipers because she couldn't see out to drive, but the wipers were useless in that the blood was on the INSIDE of the windows!]. (00:31:45)
Other mistake: Interior views of Joe's car while he is driving Jenna and Mara to pick up the drugs are somewhat odd or awkward. The driver's seat is pushed back, leaving a lot of space to the steering wheel. When Jenna is getting into the driver's seat, the headrest (or back of seat?) is enlarged and tilted about 45° inward. When Joe put the wipers on, they appeared to be moving BEHIND the flowers which were dangling on the inside. The blood splattering from Joe wasn't as could be expected. (00:31:27 - 00:32:31)
Continuity mistake: The backgrounds visible while Joe is driving to get the drugs for Mara are inconsistent. There is or isn't rain on the windows and the foliage ranges from dense and green to sparse and orange/rust (Fall-like) coloring. (00:31:33 - 00:31:55)
Continuity mistake: Before Mara goes into the bathroom to throw up, her hair is curled. After she throws up, her hair is almost straight. Mara's hair is curly again after she throws up a second time. (00:12:50 - 00:13:52)
Other mistake: Mara uses a light underhand toss to throw a bottle (fifth) of alcohol maybe 10-15' to Special Agent Rosetti. When the bottle hits the rear window of Rosetti's car, the entire window shatters and little of the glass can be seen. A bottle of alcohol would not shatter a car window completely out. If anything, there might be a small crack where the bottle made impact. (01:12:20)
