Improve Xonotic distribution
There should be Windows installers, creating start menu entries and (optionally) a desktop shortcut. This allows players to manage the installation using the Add/Remove Programs dialog as well. WiX Toolset can be used for this, or alternatively, InnoSetup or NSIS.
Apple disk images (
.dmg) could be created for distributing the game in the traditional, "mount the
.dmg file, move
Xonotic.app to Applications/ and start the game" fashion.
There should be a Linux-only distribution (this would reduce download size slightly, since Windows/macOS-specific files wouldn't be included anymore).
AppImage could be used for this, making sure that all the required libraries are included (so that players don't need to install anything to start the game).
This should be automated as much as possible, to allow creating builds more regularly if needed. Continous integration services like AppVeyor (Windows), Travis CI (macOS, Linux) and GitLab CI could be useful here.