Continuity mistake: After Snowy runs away, two gunmen grab ahold of Tintin, restraining him. As Tintin is yelling "Cowards! Murderers!", the gunman on the left is holding Tintin's upper arm with his right hand. The shot cuts to a closer angle of Tintin and there is no sign of the gunman's right hand. (00:11:00)
Revealing mistake: When Tintin discovers that Rastapopoulos is on the island, Tintin's arm has been animated differently than his face. Tintin's arm appears visibly more tanned than his face is. (00:11:05)
Revealing mistake: After Rastapopoulos tells Tintin he should have stayed on Flight 714, he says all he wants is Carreidas' money. When he finishes the line, the cigar in his mouth literally flickers from the left side of his mouth, to the right side of his mouth without him moving it. (00:11:45)
Revealing mistake: When Carreidas tells Rastapopoulos that he is mad and Rastapopoulos replies "No, just well informed", Rastapopoulos begins to walk around Carreidas. As he is walking around Carreidas, the cigar in Rastapopoulos' mouth clips through the string in his monocle. (00:11:50)
Continuity mistake: When Tintin and the others are locked in the room, Tintin looks out the window, assuming he thought he heard Snowy. On the left hand side of the window is a plant. A few minutes later, Snowy arrives and the plant is still there, but when Tintin throws Snowy out the window telling him to wait, the plant has vanished. (00:13:55 - 00:16:20)
Continuity mistake: Captain Haddock places three strips of tape over Rastapopoulos', Carreidas' and Krollspell's mouths. The last piece of tape over Rastapopoulos' mouth is a strip that goes from the top of his left cheek down to the bottom of his right cheek. A few seconds later, as they leave the room and go outside, it goes from the top of his right cheek down to the bottom of his left cheek. (00:20:35)
Character mistake: When Rastapopoulos and Carreidas are arguing, Haddock intervenes telling them to cut it out. Rastapopoulos and Carreidas attempt to kick each other but end up kicking Haddock's leg. The kick is shown to have hit Haddock around the back of his leg, but Haddock then grabs his knee in pain. (00:21:00)
Continuity mistake: At the start, keep an eye on the tape strips over Carreidas' mouth. There is a vertical piece of tape directly over Carreidas' mouth, followed by another piece of tape from the top of his right cheek down to the bottom of his left cheek positioned at a sideways angle, followed by another piece of tape from the top of his left cheek down to the bottom of his right cheek also at a sideways angle. All three strips of tape are meeting with each other at a midway point by his mouth. However, when Haddock says "Come on" to Carreidas and Krollspell when they are under fire later on, the tape strips positioned sideways now meet each other at around Carreidas' left cheek area, further away from his mouth. (00:25:45 - 00:26:40)
Character mistake: When the group is discovered by Allan, they all take cover behind a rock whilst Allan fires at them. Tintin's position behind the rock would not protect him. Allan is standing directly in front of them and Tintin in taking cover beside a rock that is to the left of him. The area in front of Tintin would still be exposed to Allan's gunfire. (00:26:00)
Continuity mistake: When Allan realises that Rastapopoulos wants Carreidas alive, there is a grenade pin in one of his fingers from the grenade that he just took out. Allan then throws the grenade away, and the pin for the grenade has suddenly vanished. (00:28:55)
Continuity mistake: When the group is reunited with Gino and Skut, Skut is smiling with his mouth open. Tintin walks over to them in the next shot, and Skut's mouth is suddenly closed. (00:33:30)
Other mistake: In order for Rastapopoulos to break into the secret passageway, he places chunks of dynamite around the idol, then lights a fuse for each individual chunk of dynamite, all burning at the same time. The fuse for the dynamite near the middle of the idol is significantly shorter than the fuses for the others. Despite this, it still takes the exact same amount of time for all three to burn down. (00:34:00)
Chosen answer: It is a pill that makes alcohol taste disgusting.