The plot, the story was not as tight as in the original albums which inspired the movie. However, Hergé was learning all the way as he wrote and drew the adventures of Tintin. He too wrote some trainwreck plots now and then. In fact nearly all of his first albums had them, along with more or less mediocre drawings. It wasn't until "King Ottokar's Scepter" that he started to get everything right.
I'm hoping that Spielberg will get everything right in his next Tintin movie, which Tintin himself announces at the end of this movie. That is, if there is the money available for it. I hear that the box office results have been very poor for this one, which is quite a pity.