I was very excited for the release of On the Rain-Slick Precipice of Darkness. Unfortunately, it appears to be broken on open-source graphics drivers. After a bit of debugging with some folks on the forums, it looks like the game is testing for OpenGL extensions before creating a GL context. Since we only load the driver at the time someone makes a direct context, we have no idea what to return for the extension list, and just return NULL. The game appears to take that answer and get all indignant that we don't support things like ARB_multitexture.
They're looking into it, and hopefully we'll have a playable game soon.