CloneKeen is an almost complete clone of the old classic DOS game,
"Commander Keen: Invasion of the Vorticons" by by id Software:
http://www.idsoftware.com/
CloneKeen requires the original id Software gamedata files to work.
If you posess the original DOS games. You can play all three episodes of the
game. If you don't, you can can still play the shareware episode one. Which can
be freely downloaded from Apogee, but cannot be distributed as a part of
Fedora. When you start CloneKeen for the first time it will offer to download
the shareware datafiles for you.