- Continuity: When Chris and Kate are in the monastery in 14th century France, and first discover the tunnel and start to crawl through it, one of them knocks over a candle. In the next shot it is back standing upright, as if it was never knocked over, without anyone picking it up.
- Revealing mistakes: When Marek and De Kere are falling down the steps, a "dead" soldier lifts his head up.
- Continuity: The season depicted is spring (4 April 1357), yet in all external shots we see the greenery of the middle summer.
- Anachronisms: When Claire and Marek are floating down the river, the raft she is in is held together by industrial staples.
- Revealing mistakes: When Lord Arnaut is in the tunnel with Chris and Kate after the explosion, one of the "rocks" on the ground is obviously made of foam.
- Revealing mistakes: Just after Doniger kills Kramer in the present, we switch back to the battle in France where Marek watches through a barred window as Claire is about to be hung. The whole grate is supposed to be set in a solid frame, but it moves. The "iron" bar on the right bends and wobbles.
- Revealing mistakes: When Kate is in the tunnel and spots the broken monastery wall, she stands up and the sound of her helmet hitting the boom mic above her can be plainly heard.
- Errors in geography: When the team see the star chart images, taken in 14th Century France, they clearly show the constellations of Centaurus and the Southern Cross, not visible from France, now or 1357.
- Continuity: While hiding in a village hut from Lord Oliver, Kate turns her wrist to look at the blood on her hand twice.
- Continuity: After Chris, Kate, Marek, Professor Johnston, and Gordon escape the manor house, all five can be seen stepping on to a balcony. The next shot reveals that all are stepping on to the balcony but Marek, who stops to go and rescue Lady Claire.
- Continuity: When Kate and Marek are examining the monastery cave-in, they see a decorated section of the wall, which is damaged. When Kate and Chris go to the same section of the wall in 1357, it is decorated differently, and they break out a larger section of wall than what was missing in the present.
- Anachronisms: The team take a Frenchman to 1357 as an interpreter. But 14th-century French would have been incomprehensible to a 20th century speaker and vice versa. Also, the Englishmen of such a time and place would have been Normans, able to speak little if any English.
- Audio/visual unsynchronized: When Doniger is trapped in the machine, after he says he doesn't have his marker, when he says the words "I'll never get home!" his mouth isn't moving.
- Anachronisms: The film completely misrepresents the languages being spoken at the time. In 1357, when the film takes place, neither modern French nor modern English would have been spoken. The English would have been speaking Middle English (a language closer in pronunciation and vocabulary to Old English) and the French would have been speaking Occitan - a combination of Middle French and Latin. Certain members of both sides would have spoken Latin, especially the clergy. Michael Chricton details these languages in his book but the film ignores them.
- Crew or equipment visible: In the scene at the beginning, in Doniger's office, you can spot a small, black microphone attached to Doniger's collar when he turns to face the window.
- Continuity: After Lady Claire and Marek kiss for the first time, she wipes away a tear, in the next shot, she put her hair back. This could not be done in one move, her hand is at eye height, and after that its on the top of her head.
- Continuity: After the group has walked into the time machine, we see Kramer and Doniger run up to the control room. In the next shot, Kramer can be seen next to the machine, just as Gordon asks Marek to change position.
- Anachronisms: For starters, the medieval language was quite different from modern day language. Even the French and Scottish languages were quite different back then. Yet the characters, and even the people in the past do all speak modern day Engelish.
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Goofs below here contain information that may give away important plot points. You may not want to read any further if you've not already seen this title.
- Errors made by characters (possibly deliberate errors by the filmmakers): SPOILER: After Decker kills Gordon with his sword, he returns the bloody sword to its sheath without cleaning it. A swordsman would never do this, as the blood could not be cleaned out of the sheath and the oxygen in the blood would cause the sword to rust.
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