Revealing mistake: When they are spearing fish near the start, a water drop goes from the water to the spear, showing that it is reversed. (00:04:34)
Revealing mistake: Even though the Vikings are rowing their boats at full speed, there are no wakes from the aft nor waves from the bows as the boats plow through the water.
The Vision - S4-E12
Revealing mistake: Two oarsmen (or rowers) in Ragnar's boat, the first in front of us and the second from the back, pretend to have an oar but have none. (00:38:35)
The Message - S5-E7
Revealing mistake: When Floki and fellow Vikings march across Iceland, an aerial view of Dettifoss waterfall is shown, including the visible tourist paths, fencing and a small stone bridge on the left, used by tourists to visit around the site. (00:31:15)
Revealing mistake: The battle has Lagertha fighting skeletons, but on her final skeleton she swings her sword downwards and massively misses it by a large margin, but it still falls.
