Despite the fact the game (Ley Lines) in question isn't the most dramatic plot I've recently seen judging from the trailers out now, the music you've given it definitely gives it life in ways comparable to what well written dramatic dialogue can do.
The piano and vocal/vox melodies are particularity flawless, can't fault anything about them.
The staccato string drone that begins @0:25 along with the piano melody shift adds a sense of urgency to the piece and the fact the staccato continues on helps drives the urgency up until the drone is dropped at @1:36 which along with the return to major chords the other instruments do @1:37 helps provide an emotional breather/release in this wonderfully done loop.
While the staccato string drone is going, the environment around me could be completely peaceful and yet I would still need to feel the need to address some important matter in the area in an adventure or battle setting.
Staccato drone = perfect urgency
While the piano along with the vox melody implies there's something of core emotional value going on or at least to be considering while in the area where this plays. When the piano and box are by themselves, the tune become a time in which to think over or breathe. The violin coming in and out even while the drone isn't going does keep the idea of a loose spirit (person, energy, animal, or otherwise) is still in the air.
If I had to be absolutely critical, there's a brief discord that happens with the violin at 1:20-1:36, but it maybe due to the violin hitting a minor chord with the other instruments or something along those lines. It's somewhat jarring if one was expecting a gentle but urgent paced boss theme upon until this point but ultimately helps really give life to the emotion that something is out of place. The discord caused by this violin hitting minor scale progression does build up tension that becomes released with the sustained note carried out @1:37 so it. So it does have purpose in that sense. In fact the higher pitch of the violin does build up to be like a nemesis in this piece, really bringing to life the idea of something falling out of harmony or rebelling against the melody imposed by the other instruments, perhaps out of sadness until the tension gets released during the final 20 seconds of the loop. (So in the off chance you decide to ever end up revisiting this piece and something feels out of place, the violin from 1:20-1:36 is a point that objectively stands out that could easily be played with to change the overall tone of this entire song.)
Overall a beautiful piece and I can easily see this piece in particular getting it's own extended version being crafted by fans if so allowed. To Be Honest, the soundtrack tidbits you've been releasing here and in those trailers is what gets me hyped for Ley Lines thanks to the possibilities of the creativity the boss battle introduces on the drama and mechanic front. It maybe the piano but also kind gives me some Final Fantasy vibes too. Would be cool to see you play the core melody on piano or an instrument of your choice sometime.
Awesome Piano. Awesome choirs. Love the string drone. Well timed Tubular(?) bell chime. Violin melody probably could be played with. Provides sense of Urgency yet emotional significance. Easy to listen to loop. Ignites imagination. Good Stuff, hope to see more from you since you are on a roll!