Actually you can download three different versions on the Apricot blog:
a CrystalSpace version
a BGE version with GLSL
a BGE version without GLSL

Each of them for Windows, Linux and MAC.

In the following link Campbell explained the current state of the game logic
ApricotBgeLogic

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt