Does xvidcap work with fullscreen applications, such as games like Cube?
It depends on exactly how the graphics are drawn to the screen. It is not the fullscreen quality or the gaming nature of the application that could make it impossible for xvidcap. There have been reports that X-Wing Alliance through WINE e. g. works just fine. Problems typically arise around hardware acceleration like OpenGL. Those often need to be disabled to allow xvidcap to caputre the display. See above.