Continuity mistake: When Tintin and the two kids are escaping from the submarine lair, the water level keeps changing. It's supposed to be more and more high, but it's lower in some shots.
Continuity mistake: When Clara is chasing Snoopy and Woodstock, she is holding a leash in her hand. When Clara is standing at the top of the stairs and sees Snoopy and Woodstock run past, the leash has disappeared, but when Clara slides down the banister, the leash is back in her hand again.
Continuity mistake: When Woody says that he'd better put the pile of dishes away, you can see that he is next to the door but in the next shot he is by the sink.