I like it very much.
The introduction speaks about the "darkness". The first part is trepidant, at first I thought I would not stand 6 minutes at that speed. But that was fixed in m. 39 with the chords and quintuplet part. There are plenty of ideas, perhaps many, but it's OK. For example the new section from m. 89 in triplets. However this part leads to a nice climax. I think the las part in chords is a bit long.
One of the things I like is that there is not a clear melody, the piece goes by harmonic and chordal changes.
To be perfect (the score) you shoul write the slurs (sure they are).
In some spots it seems to appear some kind of phrygian mode (just the first chords). There are some scales that can sound particularly dark. For example locrian bb7 (1-b2-b3-4-b5-b6-bb7).