King Ottokar's Sceptre: Part 1 - S2-E4
Revealing mistake: On the peasant cart, Tintin notices a car. The next shot shows trees to the right of frame literally jiggling. (00:20:25)
King Ottokar's Sceptre: Part 1 - S2-E4
Revealing mistake: Two villains listening to Hector's conversation with Tintin write down notes on his pad. When he writes, it's always the same place he writes every time. (00:02:45)
Revealing mistake: The words on the article are not words. It's just letters mixed up into fake words. (00:08:40)
The Broken Ear: Part 1 - S2-E2
Revealing mistake: When one of the villains throws a knife onto a target board, no knife mark is made afterwards. (00:14:15)
The Broken Ear: Part 1 - S2-E2
Revealing mistake: After losing the parrot, a man is shown writing a "missing parrot" note. After finishing the first line, we can see last word goes over the desk. (00:08:55)
Revealing mistake: When Tintin emerges from his cabin, he starts yawning and stretches his arms. You'll notice that his arms go through the wall as he does this. (00:12:15)
Revealing mistake: When the Peary financier scrunches up a piece of paper after finding out the Aurora failed to be sunk, his cigar is seen going through his lips. (00:12:05)
Revealing mistake: Professor Fossil places the results over a lamp and says "I have never seen such a formation before". As he says this, Tintin appears on screen. He never walks into shot, he just appears on the screen out of nowhere. (00:07:40)
Revealing mistake: During the earthquake, Tintin leaps onto a lamp post and the ground starts to rise. The inside of his mouth is green as this happens. (00:05:50)
Revealing mistake: After Tintin exits the observatory, there is a shot showing us the meteoroid in the sky. In this shot, stars are visible through it. (00:04:40)
Revealing mistake: When the scientists are eating their dinner and begin to get sea sick, one of them has a glass of wine. The wine slides along the table, yet the wine in the glass stays in a fixed position. (00:10:40)
Chosen answer: It is a pill that makes alcohol taste disgusting.