Character mistake: The police claim the Myers house is at "45 Lampkin Lane." The address on the front porch clearly displays the number 709.
Character mistake: Since the Book of Revelation ends with Satan being defeated, Damien and his followers should be aware of this. That's why it makes no sense that they keep quoting from Revelation since it ends up spelling their demise (it does not predict that the Anti-Christ will destroy the earth as they keep claiming).
Character mistake: When the adults are inventorying the weapons in the armory, one of them walks over to a case of pistols and says, "Pistol, 45 millimeter, M 1911A." The M1911A is a .45 caliber pistol and is listed as such right on the crate. There's no way the actor could have read "45 millimeter" anywhere on the crate.
Character mistake: The movie starts with shots of the moon Io and the company's operations, with typed descriptions at the bottom of the screen. Guess they couldn't afford a proofreader. They spell dependents as dependants, marshal as marshall, and principal as principle.
Character mistake: When the crew of the German U-boat boards Katanga's ship, the submarine moves in a position perpendicular to the ship's bow as if to block its path. In reality, this would have been a pretty stupid move by the German captain, as Katanga could have rammed the submarine easily. Any kind of damage to the hull, especially ramming damage (even from small ships), would have been catastrophic to the submarine. It makes no sense to make a manoeuvre like this.
Character mistake: At the boat where Bond talks with Colombo for the first time, Colombo has to convince Bond that Kristatos is the bad guy. Colombo takes two drinks and wants to toast with Bond. Bond will trust Colombo and says, 'Yassou' which means 'Hello' instead of what he should say, 'Jamas' which means 'Cheers'.
Character mistake: When the revolutionary fighter commandeers Air Force One (we only know this once she's in control), a Secret Service agent is trying to break down the cockpit door by banging it with the butt of his automatic rifle. The way he's hitting the door, he couldn't break through a cereal box - it's much too weak. Presumably, the actor is taking it easy on the door because it's a cheap prop door. (00:11:15)