Factual error: The deer in the forest somehow does not hear the giant dinosaur approaching, so doesn't run away. (01:21:10)
Suggested correction: A different interpretation is that the deer knows the difference in the sounds - gurgling/roars of an approaching herbivore versus carnivore - so it didn't perceive it as a threat until it got unusually close (so the deer looked to see why). The dinosaur flung the deer aside, then proceeded to eat the vegetation where the deer was. It isn't likely that the dinosaur (if a carnivore) would toss aside a fresh deer meat brunch in favor of some green brush.
The therizinosaurs were herbivores.
Other mistake: When Tsireya is shown swimming with Aonung and Rotxo, her right shoulder strap is glitching through her shoulder. It then proceeds to slip back out of her shoulder and into its correct place. (00:59:10)
Factual error: The teacher sends her pupils to the woods to collect chestnuts. Later we learn that the date when all this happened is May 30th. Chestnuts ripen in autumn, around September-October. (00:52:18 - 01:05:06)
Continuity mistake: After Brecken was done "chewing on the wastebasket" and his mother was sitting next to it in the bathroom, the "bite pattern" along half of the rim was different (not as jagged or deep) and represented what would be an earlier, lower level of the plastic being bitten off. (00:04:00 - 00:05:13)
Other mistake: Si was kneeling on the floor, stabbing his upper left arm and blood was gushing out. After he moved his right arm with the bloody knife to his right side, the aerial view did not show any blood on the floor, across his thighs/pants, or even dripping down his left arm. (00:27:50)
Deliberate mistake: After Sam freed Gary from being tied up by the aliens, Gary pulled off the cast he got earlier that day and was able to use his left arm as though it had never been broken. (00:45:43)
Continuity mistake: Alan goes into his appointment with Dr. Fredericks at 5:08, and it is still 5:08 on the wall clock when he leaves her office. (00:10:20 - 00:14:03)
Character mistake: We see the lead driving on the motorway to get to the cottage. She leaves at junction 6 for Princes Risborough. Which means she is on the M40 that goes to Birmingham. When she arrives the host asks about the drive down and mentions the M4. This is a different road entirely, that goes to Swansea.
Continuity mistake: Ishmael shots Karim in the right side of the stomach, but the wound moves to the left side.
Other mistake: At the end the camera bulbs would not work as they are electric. This is proven when the music starts after the creature leaves the area. (02:01:00)