This movie starts with time travel and gets progressively over-the-top from scene to scene. Fans of Shonen anime will appreciate its revelry in the tropes of the genre translated to the Batman mythos. Fans of Batman what-if scenarios will enjoy the translation into recognizable archetypes. Everyone else will just be confused. But for its target audience it’s a lot of fun.
Closest comparison: It’s like One Punch Man by way of Dragonball Z, with a Batman skin on it.
Setting: Adventure
Plot: Shonen Anime
Tone: Super Hero