Mastering is flawless.
The pacing is good. When I first saw it is 5 minutes long, I wasn't sure I could listen 'till the end - as I treat music like a brief experience. But I did, easily.
It isn't "groundbreaking" as a whole but it has many-many sweet spots, you really have a great taste for pacing and I really really really like that, it really makes the song an experience in itself with its own story. It could be easily used as a great soundtrack for a trailer, even though it doesn't have the usual tropes a trailer audio has.
It's hard to review on it other than it's good, lol. Would be great as a boss song in a Deus Ex game.
I would only suggest, for the sake of immersion and emphasis, to really turn up the volume of one or some instruments during certain sections, whatever you feel best, to BREAK the ambience, make something really stand out on a rhythmic section or something that would play the role of a lead guitar. That would draw the focus of the listener's ear and really hook him, make him focus on something and lose it to the song.