Factual error: When Nigel is in the gyrocopter thing and is over the sea/ocean, you can see off into the distance an island with what appears to be houses, but it is supposed to be prehistoric times.
Factual error: When His Divine Shadow lays on the table to have his brain removed, the machine cuts his skull open and simply reaches in with a three pronged hand and tugs on the brain pulling it out. It would not have worked this way... The brain is about the same consistency as gravy and the prongs on the hand/claw putting pressure on it to pull would have caused them to sink into the brain's tissue destroying it. Also it pulls the brain out without cutting or separating it from the spinal column and merely just pulls it out from the top. This would have caused his brain to be torn into pieces as it was tried to be pulled off the spinal column, not come out perfectly in one piece as shown. (01:09:00)