Continuity mistake: After pardoning his cousin with the melt stick, when he says "I'm stepping in it" Topaz can be seen with the melting stick on her left, in the next shot she has it in her right and then back to her left hand when she says "burnt toast." (00:39:00)
Continuity mistake: When Thor speaks with Valkyrie in Hulk's room, he makes his presence known by leaning on the end of one of the drinks racks. But in the following shot, he's moved a few steps back. (01:10:20)
Continuity mistake: When Karl Urban is defending the Asgardians, the dust covers on his rifles vary between being open and closed several times. M16 dust covers are sprung loaded - they open on the first shot and have to be manually closed afterwards.
Continuity mistake: When Thor and Loki are in front of the Shady Acres care home, an old man wearing a black hat passes behind them but in the next shot a woman is there instead.
Revealing mistake: During the fight in the forest with Heimdall and Hela's soldiers, he uses the sword but the tree is cut before the hit, and the soldiers on the right fall before the hit too.
Continuity mistake: Banner is covered in green powder, but when he is separated from Thor the powder covering his face and hair is suddenly gone.
Suggested correction: We have no context to know how long Bruce was missing, but the next time we see him he still has green powder in his sideburns.
Continuity mistake: When Valkyrie is drinking and watching the fight between Thor and Hulk, an object appears in her hands from nowhere.
Other mistake: When Loki gets up from being thrown during the "get help" scene, he seems too far to the left of the screen (Thor's right). Thor is still looking down to his left at the fallen guards, and in the previous shot we saw that Loki fell amongst them as he knocked them down.
Continuity mistake: In the scene when the Hulk is changing back into Bruce, he is wearing a round plated metal belt around his waist. But straight after when Bruce is lying on the floor there is no belt, just the material.
Continuity mistake: Hela kicks Hogun and breaks the wall, but a few shots later he is standing in the middle of the square.
Continuity mistake: When Thor pats Loki's back, he's placing the electrical chip that he will later use to zap him. It's about waist-high. When he zaps him, it's much higher, closer to his shoulders.
Continuity mistake: According to the previous film, Thor: The Dark World, Asgardian kings live approximately 5,000 years. (If I want to be cautious here, this statement is only valid about Odin and of unknown validity about other Asgardians.) But in this film, Thor says Odin fought Surtur 500,000 years before.
Suggested correction: In Norse mythology, Asgardians have access to the magic apples of the goddess Idunn, which make them immortal. Without the apples, they wither and die. This process takes about 5,000 years. With the apples, they can live forever.
Thanks for writing that. It was fun to read. But according to Thor: The Dark World, Odin is younger than 5,000 years. This film states that Odin has not seen the previous Convergence (the celestial alignment that also takes place every 5,000 years) and the war that was fought by his father, King Bor. He has heard stories of it but he cannot be certain. (See 0:32:00) And Bor is dead. All of these are inconsistent with this film that claims he had lived 500,000 years (100 Convergences.) Also, the franchise seems to have not adopted the Idunn's apple mythology.
The magic apples of the goddess Idunn have to be established in the MCU for this fact to be relevant.