It's too hard to support every possible combination of distro / WM / driver / library
My answer is: well then don't. Much like in Windows, 99% of your users will have a fairly sane and normal setup. I guarantee he doesn't lose sleep worrying about whether users can run his games in Windows 95, so why expend even a half-hour's effort getting it to work in somebody's mangled LFS installation?
There's only three WMs to worry about: Metacity, KWin, and Xfwm. They are all quite standards-compliant, and if your game will work in one, it'll work fine in another. "But what if a user's running ratpoison!?" Tell that user they're not using a supported configuration. Problem solved.
Ditto for sound. If your game uses OpenAL or GStreamer and doesn't work on their system, then the problem is their system. You're not obligated to support every half-wit Gentoo user who uninstalls ALSA to optimize his kernel.
If your game needs libfoo-1.1, released last year, and a user only has libfoo-0.83-rc2 installed, don't worry about it. It's OK if your game spits out an error and crashes. Just include what libraries you built against in the README, and try to make sure it'll work on the most recent versions of Ubuntu and Fedora. Anybody who installs some weird library version will have the knowhow to ldd the binary and install missing software themselves.