Wow, thanks for the feedback! Looking back it was a little foolhardy to try to do something like this in two weeks, for Pico-8, as a second ever jam (and second ever game). But hey, you live, you learn, and I did learn a fair bit. I do mean to come back to it at least enough to get it playable, and when I do I'll see about using shades for depth, because that is one thing that I often felt could be better but it worked just well enough as is that I moved on to other things that were more pressing.
You actually can leave the map screen, by pressing 'X'. Not the most intuitive or elegant solution, and I forgot to mention it on the project page, but I wanted to keep the Pico-8 system menu accessible, while still using the dedicated inputs for it to bring up my own custom pause screen with the map. It's another thing that coming back without the jam time pressure I'll want to see if I can do better.