Explanatory and Witty
Jules Verne does not spare us from any details, no matter how long it might take to get them all out. At several points in the novel, Verne spends entire chapters detailing the real science behind the subject matter. One chapter is spent detailing the history of the cannon, from its ancient origins to its modern pinnacle with the Gun Club, and another is spent exhaustively describing the history of our scientific understanding of the moon. While it's great to have so much detail, it might feel a little dragged-out to modern readers.
When he isn't doing this, however, Verne delivers his scenes with a witty, pithy style. He delivers a ton of great little phrases—"amiable and learned murderers" (22.13) ranking at the top of the list for us. In fact, it's the contrast between these two styles that make the novel so compelling—it manages to expertly balance long-form explanation with incisive one-liners. Go team.