http://www.garagegames.com/demos/browse/development/ Demo version of TGB. Not sure when it was released. As far as using it myself, I quite like it. I don't use a lot of the level builder / autoscript style tools built on top of it, prefering ti mainly script by hand. The script language itself is like a 1st / 2nd year Uni version of C++, and the "commercial" liscense gives you the full C++ source for any modifications you want to do. If you use all scripts to make your game you also have basicly out of the box porting to a mac, and by that I mean take all your scripts, drop them into a clean mac version and "compile".