When Mrs. Olson tells Casey and Stan that Mrs. Brummel has cancer regarding her dissolving body in the previous scene, a good portion of the boom mic is quite visible at the top of the screen before zooming in on their faces.
Zeke states that Scat, a diuretic, dries out the aliens. A diuretic makes you urinate and must be ingested to work and would not dry out an object on contact. Scat is a desiccant which would dry out an object on contact.
When Zeke is in the bathroom in the beginning when he is introduced, he gives two boys free "scat", he hands it to them and both pens are facing the same way, but when his name appears, one is facing one way and the other is facing another.
When Zeke and Miss Burke are in the car near the end of the film we see Zeke putting on his seatbelt. Then we see Zeke's hands on the steering wheel. In the next shot he is still doing his seatbelt up.
When Casey gets out of his father's car, he walks right onto school grounds, making the passenger side of the car against that curb. When Casey looks back and sees Coach Willis talking with his father, the driver's side is next to the curb.
After infecting a lab mouse with the creature, Zeke dissects the mouse, then removes the creature and examines it on a microscope with a scalpel still in his hand. In the next shot, he is shown retrieving the scalpel from the dissection tool kit.
When Stokely, Delilah, and Mary Beth are outside, Delilah is talking to Mary Beth about Stokely being a lesbian. Stokely then starts putting things into her backpack. From a wide shot we seeing Stokely zipping up her backpack and nothing else is left on the table. The next shot shows Stokely grabbing her cigarettes from off the table.
In the faculty lounge near the beginning of the film, when Mr. Tate has the line "Can we say retirement?," Mr. Furlong's green jacket can be seen next to him. However, at that point, Mr. Furlong is actually talking to Nurse Harper and her patient by the table. Furlong doesn't move next to Tate until later in the scene.
When Casey shows Mr. Furlong the new species, Casey always has his backpack slung across his chest, but towards the beginning of the discussion of the new species, Casey doesn't have anything slung across his chest. The next shot of him and future shots all have him with the backpack slung across his chest.
When Casey and Delilah are in the faculty lounge and Casey sees the shadows behind the door, he drops his camera on the table and him and Delilah run into the closet. Later on in the scene, the camera is no longer on the table, and nobody has grabbed it.
When Coach Willis and Mrs. Olsen enter the faculty lounge, they walk to the water cooler. Mrs. Olsen splashes water on her face and getting some of her hair wet. In the next shot, her hair is dry and perfectly brushed.
Marybeth asks Stokely how the book Invasion of the Body Snatchers end, Stokely replies, "They get us. They win. We lose." But actually the book ends with the aliens giving up because they had underestimated the human desire for survival.
When Zeke hands out the Scat pens to determine who amongst them may be an alien the blue cap is still on as they inhale from the other end. Now unless they have a huge inhaling capacity there's no way to inhale a whole pen's worth with one end of a tube sealed.
Zeke tells Miss Burke "It's too Hot", yet he's seen clearly wearing a waffle shirt under his dark t-shirt. Waffle shirts are made primarily to keep one warm, so why would he be wearing one under his t-shirt if it's "too hot"?
When Zeke hands Marybeth the pen of scat, he removes the blue cap from it as he hands it to her. Marybeth is seen spinning the pen, which we later learn is her emptying it. The shot switches to Delilah about to snort it, then back to Marybeth who now has the cap on her pen.