KOPS (1996, 2001, 2003)
KOPS is a local multi-player cave-flying and fighting game with thruster ships. The game is originally released in 1996 as a shareware title for DOS platform. Back in the time games belonging to the genre were quite popular, at least in Finland, where the cave-flying genre is known as “luolalentely”.
In 2001 I ported the game to Windows and Linux platforms in and released as freeware. After getting over the fears of showing some old and potentially ugly code in public, I finally released the game as open source 2003, using the GPL license.
If you’re interested in developing the project further, go to the game project page hosted by SourceForge.net.