These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Anti-Climax Boss: Quasimodo is this in both the movie and the game, despite being the closest thing the movie has to a Big Bad. The game is exceptionally bad about this, where every"boss" in the game falls into this trope. To truly hammer it home, your only reward for beating Quasimodo are a few words of dialogue immediately followed by the end credits!
Creepy Cute: She's 118, can turn into a bat (albeit a very adorable one), crawl on walls, can't go out during the day, and has no reflection, but otherwise, young Mavis appears to be a normal, sweet teenage girl.
Critical Dissonance: Movie critics gave the film mixed reviews, but audiences liked it anyway; the film earned an A-minus from Cinemascore.
In fact, the public liked the movie so much that it led the film to an opening weekend total of $42.5 million. It is the best opening weekend ever for a Sony Pictures Animation feature, topping the $30.3 million opening of Cloudy with a Chance of Meatballs in 2009, as well as the biggest opening weekend ever for the month of September. It went on to make $358.4 million worldwide against a budget of $85 million. A sequel has even been announced, due to be released on September 25, 2015.
Game-Breaking Bug: A pretty bad one for the game if you're looking for replay value. On some cartridges, if you beat the game and try to reload the save file, you will be greeted by a load error message, which prevents you from replaying it at all.
Ho Yay: Jonathan and Dracula. Jonathan is the only one that can get him to lighten up, the common romantic comedy trope Race for Your Love was used with those two, and the scene where Jonathan tells Mavis he hates monsters and leaves? He does that for Dracula. He hurts the supposed love of his life for him. Of course he later says that he did it to avoid being eaten, but still.
To a lesser extent, there's Griffin's evident crush (man-crush, maybe?) on Drac. See Ambiguously Gay on the front page.
Just Here for Godzilla: Most of the adult interest in this movie comes solely from the fact that Genndy Tartakovsky directed it. Many people are not interested in the film itself and just want to see it because they think it will help his career if they do. The fact that he's said "if this film does well, they might let me do a Samurai Jack movie" only adds to it.
The media has also made a huge deal over the fact that Selena Gomez is voicing Mavis, and her popularity is a huge draw for the teeny-bopper crowd.
Love It or Hate It: When discussing the movie with people you know, expect either overwhelming praise or absolute disdain for it.