During the last ride of the Revolution roller coaster, the police chase after the young man. The chase is much longer than the actual roller coaster ride time.
When Young Man places the bomb in the Revolution car, he is sitting in the left seat. Yet when the next ride occurs, the bomb is under the boy who is sitting in the right seat.
At the weighing machine Calder weighs 210lb with his briefcase, and 155lb without in. A case weighing 55lb (around 25kg) would be difficult to carry for any distance.
During the Rebel Yell Rollercoaster scene, the red train changes position in between shots.
Shortly after the bomb is found at Magic Mountain, Demerest gets a phone call at the maintenance office. The sound of the phone ringing is like all the other phones in the film. But the phone Demerest uses is just a wall holder with the receiver, with no bell to create that distinctive sound.
The Young Man places the remote bomb on the first roller coaster underneath the main guide rail of the track, but allows the ride to run several times before detonating it. In reality, the up-stop wheels or side wheels of the next train to pass through the course would have knocked the bomb out of place or destroyed it.
Since only a portion of the rollercoaster in the first scene was destroyed, it would have been easy for investigators to find the blown out piece of wood and metal and discover it was sabotage.
Whenever the Revolution is shown passing through the loop, the camera spins such that the horizon rotates. This would be correct if the loop were a horizontal corkscrew, not the actual vertical loop.
During the catastrophic accident in the beginning of the movie, most of the people in the roller coaster cars are obviously dummies.
The last portion of the movie at Magic Mountain is depicted as taking place on July 4th but in fact it's easy to tell the filming was done during the winter months. The trees in the park are all dormant.
During the meeting in the hotel, when Harry Calder stands at the hotel window with folded arms and says "No argument", the wavy ND (Neutral Density) gels that cover the windows behind him are visible. Covering windows with such darkening gels is necessary practice to avoid overexposure of the background during daytime shots.
When the rollercoaster at Magic Mountain goes down for the first time, a shadow of the gear holding the camera is visible for a moment. Every other point-of-view shots of the ride sequence displays the camera's shadow throughout.
Camera shadows are sporadic on the roller coaster rides.
Just as the Magic Mountain reaches its climax, the camera's shadow is in plain sight following the open car of its first passengers.
When Harry Calder asks Hoyt where Kings Dominion is, Hoyt answers "Richmond, Virginia." Kings Dominion is actually in Dowell, VA, which is 20 miles north of Richmond.