As someone who read the manga, I can say that they did a decent job animating the parts of the story that they did do. However, I think that some of the parts that were left out, were vital to making the story good for those who have no experience with the manga. It is for that reason I could not give the movie's story high marks.
The animation had no issues. It was fluid and done properly. However, nothing really jumped out at me about it one way or the other. So I gave it a 7 for being average.
The Sound is also quite average. I feel the voice actors did a pretty good job and were well casted. The music was also decent. Not really remarkable in a good or bad way.
The Characters are decent. I feel they did a good job with portraying the characters shown as they were in the manga... but I also feel that the male main character, Munsu's background is not touched on enough. This is also a issue within the manga as well. I always felt that they should go into his past more. The female main character is very quiet and her drive to follow and protect Munsu feels kinda forced but it doesn't really bother me either. Her character, as compared to how she is in the manga, is spot on in the movie. The rest of the characters are also portrayed fairly well.
Overall, I'd say that if you have read the manga and liked it, you should check it out, for those who have a better understanding from the manga, the movie is enjoyable enough. However, if you don't know this series already, I think the movie is not probably the best place to start.