Does generator currently support USB game pads? I found some documentation on using the j switch, but when I run it I get a error message saying this is an invalid switch. Debug mode says 0 joysticks detected.

Also, I installed Christian Biere's patched version and when I run it I get a mostly green window where the game loads but the video is compressed to the upper half of the window.

If there are no joysticks detected, that's a problem with your system or you SDL installation.

The broken display sounds like a bug in your X11 driver or again in SDL. Try updating SDL or try a different resolution.

I have 1 joysticks detected
Joystick 0: Microsoft® Microsoft® SideWinder® Game Pad USB
So there is no problem with GamePad.