I keep debating which category to put this one in. Its one of those films that could have been more.
For starters, what's obvious from the start is this is a prequel to the Peter Jackson films. Not something from Tolkein
Design wise the animators did a good job recreating the look of the Jackson films. But only a few times do I really think it took advantage of being an animated movie and gave me something I didn't think would work in live action. But that leads into one major problem with the film. While intially sparse, there are a couple of fan service moments-and they are pretty blantant when they show up. Spoilers but a big portion of the 3rd act is a retread of The Two Towers 3rd act.
I think my other problem is the films villain. Which is kind of strange because I heard a lot of people liked him. But I rarely got the feeling he was the threat the movie wanted me to think he was.
This is a movie I could watch again, but I can just as easily forget it.