Update 7: 1x Scale
After a lot of umming and ahhing I decided things would look better at twice the resolution. Tiles went from 16px wide to 32px wide and the default scale became 1x instead of 2x. This meant going through all the code and adjusting UI positions, physics, collision boxes, tile calculations, and more, as well as redoing all sprites, tiles and particles.
It took a long time to get right...
Here's a mockup comparison of the UI. I made this to help me decide whether it was worth doubling the resolution.
Here's what the map currently looks like. You'll notice that the medals have been changed as well, I'll go into that later.
And here's what things look like in game.