Continuity mistake: At the beginning of the duel scene, when Roan and Lexa lock swords, they do so with each sword pointing to their holders' right. During the shot of Lexa being forced to her knees while Roan tells her to get down, though, both swords are pointing to their holders' left, and Roan can be seen holding his with his right hand instead of his left like he does in the rest of the scene. (00:28:40)
Continuity mistake: During the duel scene, after Lexa smacks Roan flat to the ground, he lands with his right hand right upon one of the swords. In the following shots, the sword changes position and can be seen at various distances further to his right. (00:30:10)
Continuity mistake: During the duel scene Lexa's face gets smeared with black blood following a few hits, but in the shot when she announces "The Queen is dead" right after she kills Nia, Lexa's face is suddenly clean. (00:30:55)
Continuity mistake: In the opening scene while Lexa and Clarke are talking, Lexa's shoulder guard keeps shifting on her shoulder from one shot to the next, as does her red sash. (00:01:20)
Continuity mistake: When Clark is drawing Lexa, a dot between her eyebrows turns darker and then changes into a gold star. (00:01:40)
Continuity mistake: While Clarke and Lexa are kissing, Clarke removes the neck strap of Lexa's blouse. In a subsequent shot of them kissing, the strap is back on. It disappears again as they move towards the bed.
Continuity mistake: A few moments after Pike and his group leave the room because they didn't find prisoners, Octavia pulls her own head out of the hole and says "all clear." Then she pulls two machine guns out of the hole with both hands and puts those guns on the left and right sides of the hole separately. In the next shot, those two guns aren't in the same position. Both are in front of the hole near each other. (00:28:58)
Continuity mistake: When going to retrieve Murphy from the dropship, after Bellamy subdues his sister, his gag is covering his mouth. Then, as Pike moves towards him, suddenly it's magically not. (00:22:20)
Continuity mistake: Toward the end John Murphy gets a collar around his neck. In subsequent shots the lock on the collar is alternately locked / open. (00:34:00 - 00:35:00)
Continuity mistake: During the funeral on the oil rig, right after Octavia collapses under the effect of the drug, Clarke has a sturdy, simple metal cup in her hand, but in the following shot we see her dropping a completely different, clay-like and more elaborate cup that shatters when it hits the floor. (00:39:40)
Continuity mistake: In season 3 episode 16 Jasper was shot in his left leg. In this episode he has his right leg bandaged.
Factual error: When Octavia goes to challenge Raphael and instead kills him, she does so using a very long skewer she grabs from the table. If she had actually put that through his head, it would've either stuck out from The Other Side or not gone in completely. (00:34:30)
Plot hole: In s04e06 Clarke, Roan and Bellamy are chasing the Azgeda that stole the vehicle with the barrels, killing them all in the process. That leaves 3 drivers for 2 vehicles. S04e07 kicks off with both the rover and the yellow truck re-entering the camp. However, in later shots we see that both Roan and Clarke are at the island and only Bellamy drove home. If so, who drove the yellow truck back home since no other character returned from the island? (00:01:45)
Suggested correction: Different truck. The goal of the mission was to get the fuel (on the yellow truck) to Abby. Early in episode 7 as Clarke and Abby are talking, Clarke mentions that Roan is unloading the fuel. Meaning they still delivered the yellow truck to Abby as intended (minus the empty barrel). So it could not be back at the camp with Bellamy.
Character mistake: Bellamy calls Monty "Murphy" when they get back to the Arc and he is losing oxygen.
Factual error: It is repeated several times the Diyoza was a Colonel, but then proceed to say that she was a Navy SEAL. The rank of Colonel doesn't exist in the Navy. She would be a Captain O-6.
Continuity mistake: When Clark walks into the hall full of dead grounders and it shows her looking at them. A guy on the right moves his head slightly as if getting comfortable. (00:18:50)
Revealing mistake: While Echo, Monty, Harper, Bellamy and Emori are heading back down to earth, you'll notice that Emori's face tattoo is on her right side of her face rather than her left.
