Continuity mistake: Jim's Dodge Ram with a camper seems to change colors, mostly variations of gray. Initially, both are a light gray. Other times, both look white - or even blue. Sometimes, the truck is dark gray and the camper is white. (00:03:05 - 00:25:12)
Continuity mistake: The appearance of Grace's house by the front door (to the left of the screen) changes from the time Billy is standing along the road to when he meets his mother half-way. At first, the side of the house is mostly white; it is mostly brown thereafter. The garage area to Billy's left also changes color from brown to white. (00:05:22)
Continuity mistake: During the introductory meeting with Nicole Kleiber, her glasses on the desk switch back and forth between open and folded. (00:26:20)
Continuity mistake: On the train, Margaret's hair had a distinct uneven, broken part (the middle section running parallel to the first and third lines), but her part was linear when she got to work. Also, in the hallway, some hair was raised near the back of her head in front views but not in rear views. (00:04:15 - 00:04:40)
Continuity mistake: Mikey and his friend are smoking the same inch-long joint by the back door which gets passed back and forth - no way they could keep holding/smoking it for that long given how short it was to start with. (00:04:50)
Continuity mistake: A vast majority of the movie occurs over the course of a single day, so it would be expected that Becky's hair stayed about the same. However, there were frequent fluctuations in Becky's hair's length, how her bangs were arranged, and color (whether the blue streaks could be seen at all or how much at a given time, and if she had dark roots on the top of her head).
Continuity mistake: The flatbed truck that Kyle and Swin got in at the onset of their trip is very different when they parked and went to buy rope (but got tape). The truck style is different, the cargo and its cover have changed (tarp is smaller, a different color, and is wrapped across instead of front to back), and the orange cone/cones change locations. (00:06:34 - 00:08:22)
Continuity mistake: The protagonist just arrived to his college. Long shot as he gets off the taxi, and to the right of the frame you see a group of 3 girls crossing the street and walking on the lawn. Cut, and the 3 girls have yet to cross. (00:07:00)
Continuity mistake: Adam has connected strands of hair across his right cheek that are no longer there when the camera switches direction. (00:51:22)