In the opening scene when the commercial for Peter Vincent's is playing, Charlie can be seen in the background as footage from their meeting is rehashed for the commercial.
When the gas line is ruptured and the fireball is starting to be released, three people are leaping over the sofa in unison. The scene is then shown from another angle and Amy leaps over the sofa after the other two are safely on the floor.
Charley goes to the Lee's home and before he is on the front doorstep the doorbell is ringing. Charley is mid-stride when this happens.
When Charlie enters Jerry's house to save Doris, it is night. But when they leave the house, the sun is shining.
The basement door leading to Jerry's laundry room is closed, but then suddenly opened just before they go through it. You can tell because the flashlight reflects off it the rest of the shots.
When Charley's mom's minivan was rear-ended after they had stopped, both of the van's front airbags deployed. Airbags are specifically designed NOT to deploy during a rear impact. Furthermore, the people would not be thrown forwards into the airbags, but thrust back into their seats.
When Charley stakes Ed, the special effect of smouldering into a pile of ash is highlighted with cinders floating in the air. Several are clearly in Charley's face, in his eyes, etc. but he does not react at all.
Peter Vincent's assistant answers the phone, telling Peter that a package has arrived for him. Peter says, "Send him up." This is a key point because it's enough of an invitation for Evil Ed to enter. Anyone else would have said, "Send IT up."
Charley's motorcycle is a Honda "XL250S" which is a four stroke, but the engine we hear is a two stroke.
Las Vegas is is a broad,relatively flat valley surrounded by mountains. the location of Charlie's subdivision is in an area of desert with low rolling hills. Not only does no such area exist around Las Vegas, there would be no way that subdivision could be built so far away from the city proper as there are serious issues with water in the valley.