This is a really weird movie because it doesn't come from the usual DC animated studio. It was created in Japan so it has all of those sensibilities. This change actually does wonders to make the movie more interesting visually. It fills a void in the lazy animation work that is expected from the 2D animation.
There is an inherent interest in Batman Ninja just based on its animation quality. It is a clean art style that was obviously born in Japan. This is probably going to be the main draw for people coming into the movie. But it also acts as a warning sign. Along with the Japanese art style comes the region's storytelling. Convoluted with not too many strings to hold it together, the story is what I would expect. It actually ends up being only a little lower quality than what the regular DC animated movies are like.
So if you combine the amazing art and the story, it actually ends up being pretty on par with what is normally delivered. There are obvious liberties taken with characters and their portrayal but this should be expected for a people not inherently familiar with the source material. I'm not bashing the giant robots reminiscent to Power Rangers or the Japanese dubstep music. I'm just pointing out that a bunch of monkeys group up together to form a giant monkey. Let's just say that this movie doesn't shy away from being light-hearted.
All in all, it's not a very good movie. That means it is in great company for what is expected. It seems like this just brings to light the systematic problem in DC. Empowering creators to make bad movies.
5/10 Even though its bad, has more story than Infinity War