I was finally able to watch the first Tiger & Bunny movie yesterday, and I'd like to share my opinions.
Story: The first movie is 2 parts retelling, 1 part new story. The first two episodes of the series are used, with new sequences added in. Some additions are purely cosmetic (scenes with Kotetsu struggling to put on his CrapSuit in his car) and others serve to flesh out characters (we finally learn what Rock Bison's NEXT power is!).
The new scenario was on-par with an average episode. The villain had an interesting power, and the heroes dealt with him in classic T&B style: everyone works together to try and catch him, but T&B end up figuring it out. I must say, I did not expect the capture the way it played out on screen; I was expecting something completely different based on what characters were saying throughout the epsisode. I felt that the crime was lackluster, however. It seemed a little cheesy, but that's part of T&B's charm.
Art: The retelling section was mostly reused from the show, so nothing new there. The new sequences were added in seamlessly. I loved the villain's swanky outfit!
Sound: Like the art, most of it was reused. I didn't notice any new themes, but I could be wrong.
Character: Most characters benefitted from additional screen time. Rock Bison, Sky High, Blue Rose, Wild Tiger and Barnaby all had some interesting tidbit or sequence that shed more light on their personalities or Hero alter-ego.
Fire Emblem, Dragon Kid and Origami Cyclone got the shorter end of the stick, with nothing new revealed about them. Poor Ivan came across as a mumbling loner that no one paid attention to. I guess you could say that's true to Origami Cyclone, but out-of-costume Ivan is such an interesting character. In the movie, he was mostly seen muttering to his shurikens.
Overall: I was impressed with the first movie. Sunrise handled the retelling well, and interspersed the new sequences well so that you were not bored. I think this is an excellent way to start the series if you've never seen it before, and even if you have, you'll look at characters differently. I suggest it to new and old fans alike.
TL;DR 5 words/phrases to describe Tiger & Bunny: The Beginning
retelling, some filler, new scenario, new character tidbits, great start to series