In order to compress an entire season of anime (cartoons, whatever) into an hour and a half movie they decided to utilize two techniques, working somewhat in concert. First, skip large swaths of the original plot. Second, catch us up on anything important we missed because of that by explaining it through exposition. Multiple times.
And let me tell you, you really haven't seen romance blossom between two people until you've seen... er, heard it summed up as "[they] became friends right away."
Aside from that, the acting was meh, the fight scenes were mostly meh, and the CG effects for the bending were pretty meh. In a lot of the fight scenes it seemed like "and now we're all going to pause and stand around while our opponent(s) waves his arms arms around extravagantly to create a relatively small bending effect."