I tried installing on Ubuntu 20.04 based Linux Mint Mate and got the same
problem with the mouse while in the level.
At this point the only point of difference I see is that I'm running it on a
VirtualBox virtual machine.
In other news, I've built and uploaded a macOS dmg that anyone can use to
install Enigma on macOS without having to have Homebrew and without building
from source. So far it has only been tested on macOS Catalina. If it doesn't
work on High Sierra or Mojave, let me know and I can build it on a High Sierra
machine instead, which should be forward-compatible to Mojave and Catalina.
Big Sur will have to wait until I can set up a machine to play with it.
https://github.com/Enigma-Game/Enigma/releases/download/1.30-alpha/Enigma-1.30-alpha.dmg
Sidney