It's like having someone else play a really pretty remake of the best Mario games ever made. It's nice to see, nice to hear, but there is no substance at all, because you aren't playing it. This is a movie, there should have been a story, a narrative, something to make this movie watchable to anyone who *didn't* grow up with these games, but that is not the case.
Illumination did improve in various aspects compared to the previous movie though. The humor was improved, the visuals are outstanding, the number of out-of-place pop songs was reduced to basically zero, and the lack of story means it will work better when rewatched millions and millions of times in separate out-of-order Youtube clips.