Off the bat, the EPiano sounds stiffly sequenced and all the elements sound pretty dry and upfront (like the acoustic kit). This pretty much becomes a non-issue as it switches gears into a nice glitchy dnb style.
I 100% agree with MindWanderer here. I will agree, though, that some of the sounds are a bit bland/vanilla sounding. I wasn't really feeling the synth at 4:51, which is pretty loud, esp in the 2khz or so range. I actually wasn't a big fan of the guitar that followed as the fakey sample is pretty exposed with upfront it is. I agree the string stabs aren't really cutting it here, but they (and the piano near the end), could at the very least be helped by some reverb to soften the tones and help them blend better.
Gonna reiterate that all of the sound effects have to be removed before we can post this, for which I also share the concern that they are being depended on at times to stretch the length of some sections. You may want to consider trimming a bit if this proves true. Actually, now that I write this, I'm also concerned that some of the synths used in this mix are actually sampled from the original, including the main bass synth used throughout.
Warning, somewhat useless background info incoming
So, back in the day, Alexander Brandon did his pc game soundtracks in a .umx soundtrack. This was true for Unreal Tournament and the original Deus Ex. I remember in the early 2000's using a Mod tracker to listen to and mess with the Unreal Tournament soundtrack, because it allowed you to access & isolate (perhaps even edit?) individual sounds used within the songs.
In all, I'm pretty sure the main bass synth (used throughout) is sampled from :13 & 1:03 of the original. Also, the phased pad at 1:03 appears to be sampled from :01 of the OST. I Initially thought the synth at 2:45 sounds like it's taken from :38 of the OST, though it plays some different notes, so it's probably just a similar tone.
TLDR; beyond the fact that Square Enix content needs to be removed anyway, it's worth noting that large portions of the track that connect to the OST are likely sampled from the original audio.
NO