Just finished Niji-iro Hotaru. It was great, and I have to say that it was a sakuga movie through and through, not just because the animation was stylish and awesome (also the backgrounds and art direction were mind-boggling), but because the story is otherwise typical oscarbait, but is given new room to breath and feel fresh thanks to the visual execution alone (everything else down to the OST has been done tons of times before).
The visuals also are in full support of the main theme of the film, which unsurprisingly comes to layers upon layers of mono no aware discourses intertwined with each other. I like that stuff, so I liked it, but even if you don't care for that type of melancholic stuff, the effort that was made to convey it through every area of the film has to be commended at the very least.
I didn't identify animators or anything of the sort because I'm not really good at it, but there were a lot of segments of really lively and flowing character animation. The whole thing looked like Hisashi Mori's style, but it was also not as consistent due to the stark differences in timing between cuts. I see the animators were left to do their thing.
Ohira's scene was amazing as always, and I really liked the final sequence with the fireflies. Not technically amazing, but
the use of colour was really effective there and managed to pull off a visual spectacle while not losing the hand-made charm the film has going for it.
Also, the fact that it's only DVD doesn't hurt it at all. It looked pretty good (although the style probably helps that), and I'd even say it further reinforces the ideas of the film, lol.