Continuity mistake: While Jax is held against the wall by two of the Furies it shows her bare feet held off the ground. As she moves across to Sinbad after he plunges the sword into the third Fury she is wearing flip-flops. (00:29:17 - 00:29:54)
Revealing mistake: When Gabby and Fin are hanging off the building in Las Vegas, you can see that Gabby isn't holding on to anything in some close-up shots. (00:11:47)
Continuity mistake: The sun angle changes several times during the chase sequence when the dragon is on the flatbed truck.
Continuity mistake: In the first scene, the old alien man comes to pick up his spaceship and Ratchet instructs him to "Now, let's fire up that mag booster." The old alien pushes the switch forward to start the mag booster. Later in the movie, Ratchet flips the switch backwards to "engage mag booster" as Clank commands. (00:06:30 - 00:26:30)
Continuity mistake: After their fight with the monkey Sara has some scratches on her forehead and cheekbone but when she gets to the castle with Freya they are gone.
Continuity mistake: When they are at Sarah's house, the boy's father tells her to go outside and ask Lucas to pull the van around back. When Sarah walks to talk to Lucas her long braided hair is tucked into her shirt and her arms are crossed. In the next shot when the camera comes back, her hair is on the outside of her shirt despite her arms still being crossed. (00:45:55)