Oh nice. Using the “window” layer for the castle entrance works beautifully.

I keep a retro game jam what-if pile, and a significant chunk of it is “the Game Boy Color could do anything.” A straight SotN port is high on the list of plausible options - it’s even contemporaneous. Though I’d focus more on animating the hell out of fairly small sprites. Similar to prerendering, like Donkey Kong Land. This author’s thinking more GB Mega Man.