Thanks for the reply! Below are screenshots of the menu screen, intro, and gameplay. Log is here.
I have tried everything with the available settings. In the game Bomb Chicken, only the lighting effects would display, everything else was blank. My workaround was to click-and-drag the window's border, and resize it. This caused the display to rapidly "blink" between proper and blank, but eventually it stabilized. I used the same trick with Cuphead. Both of these use Unity. As far as I can tell, Slider doesn't allow me to manually resize it like that.