I can tell a lot of work went into the modelling of the sets, characters, etc and I get what you were going for, but I have to be blunt about this - this was really boring.
While I can appreciate the enormity of the design, the fact that we watch one lone soldier running and running and standing and running and standing and typing and looking around makes for one really boring film. For starters, everything is desaturated and flat, boring grey. I understand you're establishing the setting as a big expansive factory/mega structure... but even then, there's no variety, just massive grey blocks that fit together. The music is slow and repetitive and the animation is floaty, weightless and also repetitive. It's a recipe of repetition and it gets boring really quickly.
I know I sound really harsh when I say all this, but I'm saying it to help you realise what's wrong with the short. I admire the effort you went to make this, it's clear this would have taken a long time, but if your intent was to show "a mysterious character explores the dark depths of a giant abandoned facility" - then it really didn't read. I honestly read this as a soldier going to work. At no point was he exploring, searching, pausing, looking around - he was simply running in a perfectly straight line like he knew where he was going. He had no intent, he felt like he was on rails.
For me, what this film really needs to help boost it in the right direction is establishment. Where are we, how big is the facility, who is the character, how did he get there, why is he there. These questions NEED to be answered well and truly at the beginning in order to help the film's pace, otherwise it becomes something entirely different, and we lose interest quickly.
Thanks for posting this. Regardless of what people say, you should be extremely proud at the amount of work that went into it, and eager to dive back in and make it even better.
Good luck with the next phase man!
Cam