OpenJazz is a free, open-source version of the classic Jazz Jackrabbit™ games. OpenJazz can be compiled on a wide range of operating systems, including Windows 98/Me/XP and Linux. To play, you will need the files from one of the original games.
With the demise of DOS-based operating systems, it has become necessary to use emulators to play old DOS games. Jazz Jackrabbit™ deserves more - and would benefit greatly from new features.
OpenJazz was started on the 23rd of August, 2005, by Alister Thomson. Academic pressures put the project on hold until late December 2005. The source code was released on the 25th, and the first version with a degree of playability was released on the 15th of January. Since then, a variety of ports have been released by other people.
More academic pressures meant there were few updates over the following few years, but in 2009 a multiplayer version was released.
source: alister.eu/jazz/oj/about.php