If you are not a fan of project sekai, the movie is not going to be very interesting. Even if you are, there are dozens of characters so it only covers them at a very surface level. The plot is very simple and lacks much depth. The ending is just a few short songs from each group you can wave a penlight around for, about 10 minutes.
It is an interesting experience to visit a theater for due to the crowd, but would not watch alone at home. The animation is good. The music (very short segment) is good. The story is lacking and characters are given no time to shine. If you want a minecraft movie type experience, you should check this out in theaters though