TL;DR: Stuffed the essence and all the good things of the Tamayura franchise in around an hour: heartwarming from the first minute to the last, substantial and realistic character development, great pacing, and the same relaxing atmosphere we all have loved. I look forward to watching the next two movies!
Story: The first movie did not really give viewers much of a clue as to how the four movies will end the story of Potte and friends - and all the better for how great they started things off with this movie. The conflict - centered around the characters' plans for the future
- was introduced slowly and gently, and the characters dealt with it with an aggressive decisiveness that we've seen in the past TV seasons. It's almost like a whole new season wrapped up in an hour! Even then, the pacing definitely was not rushed and the movie instilled the franchise's trademark gentle healing feeling.
Art and Sound: In one word - "gentle". Art features soft colors - not pastels like in "Hourou Musuko", but not bright vibrant colors like in "Sore ga Seiyuu". The visuals are very pleasing and easy to look at and are of very high quality. Sound is very atmospheric and relaxing, fitting the movie.
Characters: The characters shone incredibly brightly in this movie. Amazing development from Norie and Kaoru - the two highlighted characters for this movie - and their distinctness is highlighted in how differently they reacted and dealt with the problem presented to them in the movie. This was one of the things I've liked about Tamayura - its characters are vibrant and very distinct, shown not only by their visual design or speech but by how they interact with one another and how they deal with problems or events.
Conclusion and remarks: Heartwarming from beginning to end, with character development and insight that rivals that of an entire season, with a great pacing that does not seem too rushed. This currently is the pinnacle of the Tamayura experience and I have nothing but good words to say about it, save for minor inconsequential complaints. This has only served to raise the bar for the third and fourth movies, and judging from how great it has been, it's going to be an amazing ride to the end.