Hoo boy, this is a fun one to get working in Ubuntu 20 (and variants).
First, go to the game install location (in my case, "~/GOG Games/BLACKHOLE"), look for "deps.txt" and install any that you are missing. Additionally, you'll also need "libidn11-dev:i386" and any dependencies.
The fun isn't over yet, though! We also need old versions of libcurl and libssl, neither of which are available in the current repositories. You can get libcurl3 here and libssl1.0.0 here. Download the i386 version of each, even if you're using a 64-bit OS (if you're using one of the "goofy" architectures, you're on your own).
DO NOT INSTALL THESE DEB PACKAGES! We are going to extract the needed files and "install" them locally to the game so they aren't interfering with anything else on your system.
Open each of the deb packages with whatever your favorite archive/zip handling program is. Each one has the same structure, so I'm only going to go through one, follow the same directions for the other. Okay, so once you've opened the deb package, you should see "control.tar.gz", "data.tar.xz", and "debian-bina...read more