Note: I watched the raw and I don't have the best grasp of Japanese, so my basic understanding of the plot and character is a bit weak.
I would suggest giving this movie a pass, unless you're trying to watch all the Young Animator Training Project works. It is bland in all aspects bar animation, which is severely lacking.
The characters are very shallow, and lack depth. When a movie is short, few characters that are then fleshed out are needed. However: here there are no fewer than nine.
The motivation behind actions are very shallow and simplistic, which also contributes to the A-B storytelling going on.
The animation of characters is made up of CGI, which just so happens to be soulless. The models are in the uncanny valley, looking human... but not quite enough. It reminds me of imagery from the 20th century that just happens to be in HD. Apart from that, it feels like frames are missing, and the animation is very janky as a result. The main character design would be appealling and unique in any other context, but the use of CGI models makes clothing move awkwardly, and it feels like characters never blink.
The CGI does not blend well with the backgrounds, which are in 2D rather than 3D, and makes me think that it would look much better if the characters were 2D as well, because the backgrounds were lovely. (Especially since the poster is much more appealling than the movie itself.)
Oddly, background characters tend to be very static, and is noticeable from just a quick glance.
The action sequences are rather bland, and seem like they're going twice as fast as they should, action and suspense wise.
The comedy is generic, and feels like something I have seen in many shounen series past. Nothing unique or interesting about it, and the result is that it is unfunny. Furthermore, one particular gag was slapstick, so was also let down by the animation.
The plot itself is rather predictable, going from one plot point to the next in a rushed manner with no development of character.
The music is fitting, though bland. The voice acting is passable. It's average to the point that there is not much to comment on at all.
Would've been given a 3, if not for the possibility that I made a mistake somewhere.