Bullet seems to be the most mature of the game-oriented physics engines, but its story for those of us not using C++ is significantly less compelling. Bullet 2 doesn't have much of a C API, while Bullet 3 requires a high-end desktop card, considerably narrowing your customer base. Guess I'll have to re-evaluate the alternatives or resign myself to a truckload of shim C++.<p>C++'s generally poor interoperability has been annoying me since the 90s. :-(