NanoTech is a first-person texture-mapped 3d platform game with cool music and sound effects. It needs at least a 486DX 33 Mhz with 4 Mb RAM to run.  It comes with full source code and was released under the GNU Public License. It was written by Sean Lane Fuller.
Download the game and source code
The people of Earth have been at peace for many years ... a peace ensured by a superpowerful spacestation that is controlled by an advanced artificial intelligence.  The peace may shortly end because the space stations computers have become infected with a virus and it is now threatening several major superpowers.  Their only hope is a remotely controlled nanobot that has been lying dormant within the space station's computer.  You must pilot the nanobot to the computer's central core and destroy the virus.
"NanoTech" is copyright Sean Lane Fuller 1995.  See the distribution instructions in the README.txt and COPYING.txt files.