Rintaro's sequel to the first Galaxy Express 999 is quite tricky. It's very different in tone, even though both films share quite a few similarities. It's almost a reimagining of the same source material. Hence, it's not going to be for everyone, especially not for those expecting a straight-forward sequel. Personally, I really liked the approach.
This second film is quite a bit darker and more dystopian. Online reviews are quick to link to to The Empire Strike Back (understandably so), but there are also traces of The Matrix here, and the work of René Laloux (Fantastic Planet) is never far off. In the end though, it's really just a core Rintaro project.
The film is epic in scope, a welcome surprise as older animations are usually a bit more singular. The art style betrays the film's age, but the animation itself is still pretty impressive and there's no lack of creativity here, so much in fact that it's as much fantasy as sci-fi. A bit long in the end, but it's easy to see how these films helped to build Rintaro's reputation. Good stuff.