Nice! Would fit perfectly to a dark souls like boss fight. I really like the dark atmosphere of the piece. The strings at the beginning are nice and creepy and the dissonance is cool and not too strong to be displeasing. Also the louder part where the full orchestra crushes in is well done and very immersive.
The main problem I see is repititiveness (me saying after I just finished a minimalistic, repititetive, slow Jazz piece using only two chords, lol). If it´s just in the background of a game it could be okay but even then it can be tough if you are repeating the same level again and again and hear the same music all the time. The are different kinds of solutions. You use a nice little motif here and it´s cool how you play around with it and cycle it through the instruments. An easy way to get variation would be to transpose the motiv here and there. Also you could add another motif and switch between two parts. Also you could play around with the dynamics. At the moment you have two parts, one relatively quiet but swelling slowly. The other one very loud. You could already put a smaller climax into the first part, then take back the dynamics a bit and let them swell into the scond part. The you can also reduce the dynamics for a while by taking some instruments out, maybe even a short solo creating tension and then boom again at the end making a climax for the finale.
Just some thoughts... Hope this helps! Keep on doing cool stuff!

Cool but way too repetitive