Wow! It is probably the most atmospheric game I've seen in this jam. Nice color palette - I'm getting cold just by looking at it :)
The platform physics is really well balanced - on pair with Celeste and other iconic platformers. Music is nice (although, not very gameboy-ish ;) )And you even managed to put in a backstory!
Good job!
On improvements, I'd add a full-screen button with ability to zoom the view. Controls are fine, but I would prefer more conventional layout... Maybe Arrows + Space to jump and WASD + Right shift to jump. But this one is totally subjective...
Also, for some reason the top panel is messed up in my browser (Chrome 83 + macOS 10.15). The text is shifted and scaled into unreadable form :(