i'm having the same issue and when i make it windowed i can't adjust the window boundaries at all - not sure how to add the setdisplay line to the executable ^-^'
There's a way to open an exe in cmd and force a resolution but mine might be overridden by NVIDIA. Depending on your graphics card you may be able to force an application to run at a certain resolution or maybe the compatibility settings will work. IDK, this was all much easier before Unity removed its configuration screen for whatever reason.
I uploaded a new version of the game with a resolution selector. Let me know if there are any more issues.