Updated 2010-07-06 20:00 UTC – Stable Quality
Free & Open Source license
OpenJazz is a free, open-source version of the classic Jazz Jackrabbit games.
To play, you will need the files from one of the original games.
Copy them to MyDocs/.openjazz or MyDocs/openjazz folder.
Check http://www.alister.eu/jazz/oj/faq.php for supported versions.