When Tommy collapses on the stage, he is facing Carrie, but when Carrie tries to cradle Tommy, he is facing the backdrop.
The stain from Carrie's bloody hand to Miss Desjardin's skirt switches from a smudge in the shower room scene to a full handprint stain in the principal's office (the stain is even higher on the skirt from where Carrie originally grabbed it).
In the opening scene, where Carrie is born, the umbilical cord disappears between shots.
After Chris slashes the pig's throat, the flecks of blood on her forehead are gone in the second shot.
Carrie's hand lowers down, pulling down the stage light rigging down. In the next shot, both hands are raised up.
The sewing machine that Carrie uses to make her dress is an electrically powered industrial one and only requires a single depression of the control to make it move. However the shot of the foot control being operated by telekinetic powers shows it being pumped up and down as in an old fashioned manually powered machine. If she were to do this with an electrical machine it would start and stop but in the film the fabric is moving forward continuously.
When they see Carrie and try to drive and run over her, the girl tells the driver "Run her down". He hits the accelerator and it goes from to 65 to 85mph instantly. No car accelerates that fast.
The principal offers Carrie some Aspirin for her period cramps. He can't do this for two reasons: he doesn't have her mother's consent and giving Aspirin to youths can cause Reye's Syndrome.
When Chris refuses to surrender her cell phone for her father, the principal and Miss Desjardin to see if the video of Carrie being pelted with tampons is on her phone, if they knew it was on YouTube, they could trace Chris' YouTube account even if she used a fake name and Chris would've been in trouble.
YouTube would flag and remove the video of Carrie getting pelted with tampons as it violates their terms of service and policy against bullying.
When Carrie's eyes turn a solid red color in the gym, you can see the edge of the contact she is wearing.
When Carrie is in the shower and has her first period, she appears naked. However, when people are throwing tampons on her (while she is on the floor), she is wearing underwear.
When Carrie pulls the lights down and sets the banner behind her on fire, a large moon falls down and catches fire as well. As it falls, wires and rigs are visible setting off the flames and not the banner itself.
During prom, as Billy is prepping the trap and the bucket, Chris sends Sue a text which hints that something very unpleasant will happen to Carrie. As Sue reads the message, we see the time is 09:56, and this is the 24h format. The prom takes place at night, as do all proms, so the time would have been displayed not at 09:56 but at 21:56 instead.
Obvious stunt double for Tina when Carrie sets her on fire during the prom massacre.
At the start of the film the principal refers to the gym teacher Miss Desjardin as Miss Day-shar-dan (pronounced phonetically) yet all the other students (Chris, Tommy, Sue & Carrie) all pronounce her name as Doo-shar-dan. Given that she would have introduced herself and told them all how her name was pronounced it seems strange that they all continue to pronounce her last name incorrectly.
At the end of the movie when the mother stabs Carrie the blood stain on her back moves. At first the stain is in the middle of her back then a bit later on it moves to Carrie's left shoulder blade.
When Sue expresses regret about the way she treated Carrie, Chris tells her that Carrie had been "begging for it ever since the sixth grade." Carrie was homeschooled, so she would not have been in school with Chris in the sixth grade.
Just after Carrie leaves the burning school and you see her feet; she has no shoes on. From the next shot until the end of the film, she is wearing shoes.