I have an issue with the 2020 demo that I'm hoping can be resolved, if you can find the time. Or maybe you fixed it already.
I use two monitors, and I run the game in Fullscreen with Alt+Enter. It runs fine, except for one annoying interaction: When my mouse goes off the right side of the window, it goes to my other monitor, so if I'm not careful in a Shapes fight, I might accidentally click on my Discord window, minimizing the game and causing me to most likely get hit a bunch. I can tell that in windowed mode the cursor is properly locked to the window, but as of that build it wasn't properly working for fullscreen. I can't test if it works in reverse without mucking around a bunch in my display settings because it fullscreens to primary monitor.
That all having been said, excited to see what comes of the new demo this month! I'm very seriously considering pledging to see what's new. At any rate, best of luck with the next step of the game!