Blake Petit’s review published on Letterboxd :
2018 Superhero Rewatch: In which I return to superhero movies I've seen before to see how time has treated them.
Let's get something clear: this is NOT the Batman from The Lego Batman Movie. That Batman is from the Lego Movie Universe. This film is the beginning of the Lego DC Universe. The Lego people are surprisingly strict about this.
There is, however, a distinct tonal difference. This Batman is less oafish and self-centered. It's more of a classic Batman in what is still a pretty sillu universe. In this film, the Joker teams up with Lex Luthor and Batman has to face the fact that he can't handle this alone. He needs the Justice League. This honestly could work fine as a story without the Lego elements. As it is, it's a nice introduction to the DCU for younger viewers.