Continuity mistake: As Tintin and Snowy are walking out of the train station, there are two taxis parked outside. When Tintin is offered a ride, there is only one taxi, and the other taxi has been replaced by a purple car. (00:02:25)
Continuity mistake: When Tintin follows the mob member from the diner to the building, the scene cuts to an exterior shot. A hot dog stand is shown outside the building, with a vendor standing beside it, but in the next shot, the vendor is suddenly standing behind it. (00:16:40)
Continuity mistake: When Tintin phones the operator to connect him to the police, she is holding a green wire. Then when the Mafia member takes it off her the wire is now blue. (00:07:05)
Chosen answer: It is a pill that makes alcohol taste disgusting.