It's really any button registered to "O" or "X" on the PICO-8 controller for P1, which includes Z, X, C, and V. No need to give options where there aren't important ones, though. :)
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On macOS Catalina (10.15.4), v1.0 won't run, but it looks like that's because /Ruins.app/Contents/MacOS/Ruins isn't marked as executable.
Not sure if you can fix that on your end and update the package? (`chmod +x` fixed it for me, I should be able to zip it back up if you don't have a Mac / Linux machine lying around.