What physics engine is used in Gish? Did you develop your own, or is it one of the commercially available or open source engines? Whatever it is, it certainly contributes significantly to making Gish a really awesome game.
I need a physics engine that does a good job of rigid body dynamics on complex systems with hundreds of gears, levers, cams, etc. Not for a game though.
The physics engine for Gish was developed for Gish and is not a commercially available or open source engine. Have you looked at some of the open source engines that are available?