This game was gorgeous, visually and audially. I was really impressed with the varied line thickness throughout the levels, they really added a sense of variety in a monochromatic environment. The music was also timed perfectly with both on-screen events and the mood you were trying to create. Also, thank you so much for the checkpoint system, really well done.
My one gripe would be that I felt like I was wrestling with the controls, especially in the beginning. I'm used to "flying" type games using W as forward always, so it took a while to re-orient my brain. However, I felt that on the final boss this control scheme actually worked really well, maybe because it was more zoomed out and less claustrophobic?
Anyway, I really enjoyed it. Great work and good luck!