Verk dark indeed.
I think the introduction might have been a little too long, but it did fit the "dark" idea very well. I love the way the instruments build up into a cohesive melody and harmony; the intermittent silences are also very powerful in themselves.
The emotion at 2:30 is beautiful in its simplicity.
the dissonance at 3:30 was unexpected, but worked nonetheless.
The ones after the 4 minute mark were perhaps a little too dissonant, but that may down to personal preference more than anything, and the harmonies at 4:30 more than make up for it; very emotional, there.
All in all, quite a good effort. I think some fine-tuning work and shortening it a little wouldn't harm you too much, but then again it does mirror the idea quite well. Good job, overall.