I've always enjoyed the series Batman Beyond for what it was, but I never saw it as anywhere near as good as Batman:The Animated Series. Beyond was a good show, but BTAS was terrific. However, this film is very much a step up from the show and is just as good as BTAS. This would have worked very well as a live action film, but the animation looks slick. The story is suspenseful and funny with a very twists that keep you involved. Great action. Great music. Fantastic voice work, especially by Mark Hamill's return as The Joker.
If Batman Beyond was good, this is incredible. One of the most underrated Batman films.