The screenshots remind me of my unfinished level Thee Fault.
Part of the description checks out, somehow: "I started this level about 4 months ago", "I'm about 100 screens in."
That's a crazy coincidence.
In Thee Fault, I try to "pretend I'm Nifflas" to use his tilesets in the most "expected" way possible.
I like the fact Whitebow Island is the exact opposite:
You experiment with Nifflas' tilesets and use them in original and unexpected ways