A great story that keeps me intrigued! As far as the art goes, this is pretty good aside from some unnatural movement and weird saturations (perhaps from the compression/ codec choice of such a huge video). With that said, very rarely do you see 3D indie animation on NG, and I can easily see you paving the way for it to be a great medium for others to use.
Concerning the 3D itself, if you choose on staying with an anime style 2.5D look, I would greatly recommend watching behind-the-scene works of Paperman. The fluidity of the 3D comes from tracing over existing 3D frames. This would be an exciting area to play around in. Just an idea :D
The voice acting is superb, great performances from all! No qualms with that.
The music was very fitting, and the script was impressive. Keep at it!
P.S- I was thinking of supporting you through Patreon since you were running into some computer problems. External HDDs are very important, but being able to upgrade your RAM, CPU, GPU, etc for high-end renderings is critical. Perhaps this is one of the reasons why I'm building a PC computer before my Mac chokes from my next rendering process lol.