If you know what a PKGBUILD is, you'll know what to do with it, but basically it's a script that generates a package allowing any program to be handled by Arch's package manager, pacman. You can use this on arch or any of its derivatives, just put your zip in the same directory as the PKGBUILD, and run $ makepkg -si You can find the PKGBUILD here: http://sprunge.us/BXgf I'd like to submit this to the Arch's User Repository so that other people can install KSP on Linux easily, but I won't do that without the express permission of an official representative of KSP, since I don't want to violate any copyrights or anything. This script doesn't download the game, it just searches for a zip, extracts it, and installs it.
