I didn't have access to an instrument either - only college ruled paper and a pencil. I decided to write music that I knew would work, with harmony that I could understand from past experience, which for me meant writing in a style using Japanese Anime/JRPG music as a model. Because of that I was able to imagine how it would sound because I didn't do anything wild or outside of my knowledge. I felt inspired so I kept coming up with different tracks to an imaginary anime/videogame.
I just listened to the beginning and right away I was already analyzing the harmony and understanding how he got that dissonant/tragic sound at the beginning which to me is just a certain voicing of an E minor add 9 chord with the root omitted but implied from the first two melody notes. I love the crunchy sound he got from that chord. Then, the cello melody plays around with a melody that borrows the #11 from Lydian but still staying minor. There are some folk musics (especially in Poland) like the Mazurka, which like to sometimes use both the natural 4 and the #4 of the scale to give the music that folksy, mountainish feel. Some weapon dances also make use of this. Then, in measures 12, he uses an F# minor add 9 sonority instead, basically transposing the beginning up a step but voicing it an octave lower, the violin taking the folksy melody that the cello had before. That's how I would try to understand just the introduction of this piece (which I haven't yet listened to in its entirety). For me that would be helpful if I wanted to write something on the model of this piece in the future, or just to understand how those kind of chords/melodies sound the way they sound so I could get the same sound with different tonalities/melodies. The understanding that there's a half-step dissonance between the added 9th and the minor 3rd of these chords is inherent to my understanding of these chords.
Thanks for your post and I hope that at least some of that is helpful!