Newton Adventure is a free and open source 2D platform game. You play Newton, a very special hero who has the power to change gravity direction.
It runs on every Linux, Windows, Mac OS X or any OS with Java and OpenGL support.
Code is available under BSD licence, data under CC-BY-SA or more permissive licences.
http://bci.im/projects/newton_adventure/doc/trunk/www/index.wiki
(mentioned on a thread started by MCMic here.
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