Even though Frankenstein's monster is one of the most well-known classics of literature, I am not familiar enough with the original work to do side-by-side comparisons, to see where the animators took liberties. Instead, I considered this as if it were its own stand-alone work. And as such, it actually does stand up by itself fairly well. You don't need to know the two centuries of Frankenstein lore to get into this.
Starting off with the artwork and animation, all I can say is that the quality of the work is on-par with most other animated features (Japanese or otherwise) that were being produced at the time, no better or worse. Being an older guy who has grown up on seventies Saturday morning cartoons, I'm perfectly fine with that, but of course your mileage may vary. Just don't expect brilliance or high quality here.
As for the story, as I mentioned above it stands up on its own. The Monster is played in the first half as a straight-up terror, then pivots to a pitiable creature just looking for love and understanding in the second half. There's a surprisingly large amount of violence involved, which only escalates towards the end. Plenty of interesting characters to watch (I'm partial to the sardonic inspector). Not the greatest movie in the world, but you could do much, much worse than Frankenstein.
