Fellow jammer here (I made Gravity Core). I really have to hand it to you - this is the most ambitious entry in the jam. The live-updating map pipeline is the kind of tooling trick that makes me jealous; it shows in how big and connected the world feels.
The color mechanic is the star: starting grayscale and watching the world bloom after each boss is a strong hook, and tying each color to a new power/map access is smart design. I grabbed the macOS build and it ran smoothly on Metal - though the web version really struggled on my machine (Bevy WASM with this many entities is a beast, so no judgment there; the native build is the way).
I'll echo Sampesss on the small black spiders on black background - your apology in the comments was heard, ha. A faint outline or a slightly lighter ground tone near them would fix it without hurting the look.
11 bosses and a map this size in 72 hours is just showing off. Good luck with the rest of voting!