So I've been playing the demo today on my original GBC, and my impression is that it's super rad all round! There's a lot of detail that adds to the cosy atmosphere, and I particularly liked the little flavour texts for, say, a mossy or lizard-inhabited rock, or a shimmering pool.
I also found the formatting of the text very easy to read on the original, unmodified GBC screen. It's nicely written and short, while still conveying everything it needs to.
What really won me over was finding the hot air balloon before discovering the sunset screen. A small touch that I think shows the care that's going into this project.
Will definitely be following along with any future developments you make!