Basically everything about this movie was about average. The acting is fine, the characters, while sort of bland, are interesting enough. The story is good, the writing is good, and so is the directing.
But there are some things that fall flat. For example, the cinematography, for the most part, was bland. Every shot lookedthe same and felt the same. However, I thought the lighting was well done. Also, some of the perfomances felt a little off. But, I do believe that Jenny Slate and, especially, Jack Black were able to carry the film and make it more fun to watch. Although this movie is listed as a comedy, there really is little comedy to be found. It's not that the movie is necessarily unfunny, it's just that there are no jokes or humorous situations. I did find myself smiling sometimes, not because it was funny, but because there are some fun or satisfying moments in the movie.
For every negative this movie has, there is a positive that slightly evens it out. While it does leave some to be desired, this film is pretty solid and enjoyable. If you are thinking about seeing this movie, I would recommend it. Just don't go in with too high of expectations.