Question: What is tar.gz and how do I open it?
Answer: tar.gz means, it's a gzipped tarball, thus an archive. Use, e.g., tar -xzf archive.tar.gz to extract archive.tar.gz.
Question: How do I compile the source code?
Answer: The INSTALL file (found at top level of source code archive) provides basic information and the README (same location) explains special options and install steps.
Question: What is SDL?
Answer: It's the great Simple DirectMedia Layer (http://libsdl.org).
Question: And I guess SDL_mixer is...
Answer: Yes! A mixing tool based on SDL. These two libraries are all you need to compile an LGame (Okay, some libraries like libmath, libpng and libz are also required but any distro should install them by default).
Question: You're trying to say...
Answer: SDL is required by ALL games and SDL_mixer is recommended for LGeneral, LBreakout2 and LTris. If you don't get SDL_mixer the games will run but obviously without sound. For win32 you'll need SDL.dll and SDL_mixer.dll (http://libsdl.org) copied to your windows directory.
Question: I have both libraries installed but the configure script can't find 'sdl-config'?
Answer: The development packages are required since you want to compile the source instead of just running binaries. Usually these are not installed by default. So check your distro's packages and get the development stuff or compile and install SDL and friends directly from source (http://libsdl.org).
Question: I updated both libraries but they cannot be found?
Answer: If you installed the latest source you must run 'ldconfig' to apply the changes to your system. You also need to delete the 'config.cache' file.
Question: Okay, 'sdl-config' is found but it bails out with strange errors?
Answer: Then SDL is making some trouble so check its FAQ at http://libsdl.org.
Question: I'm running RedHat 8.0 beta and I installed everything from SDL to SDL_mixer devel but when configure checks for SDL_mixer it utterly fails?
Answer: One of the patches for libsmpeg is corrupted in RH 8.0b so if you downgrade libsmpeg to 7.3's compiling should work again.