Factual errors: The film depicts the famous picture of the Loch Ness monster as being taken in 1942 by a couple of fishermen. In reality, the picture is known as the "Surgeon's Photo" and was photographed in 1934 and published in the Daily Mail newspaper. It was revealed to be a hoax in 1994 and is supposedly the picture of a toy submarine with a sculpted head fixture.
Anachronisms: In an early scene, Angus pulls out a first aid kit, and the bandage on top is labeled 'Telfa'. The film is set in 1942, but Telfa bandages weren't marketed by the Kendall Company/Curity until 1954.
Continuity: When Angus first takes the egg into the workshop, you can see the door to the workshop is set in a recessed porch and it is cloudy. The next shot, as he enters the workshop, has the sun streaming through the glass in the door. Whilst it is feasible that the sun could have just come out, it would be impossible for it to be streaming through the glass, given the position of the door in the previous shot.