That last shot looks like some DOS game, to my eyes it looks terrible. Anyway, does it take both 31kHz and 15kHz through that VGA connector or is there separate RGB input for arcade PCBs? What PCBs are you going to try, any old classics? -- Good luck with it in any case, and I'm looking forward to read the review.
By the way, why the guy in that screenshot has three legs? Is that some motion compensation blending effect from LCD, visual glitch due to camera long exposure, or maybe that's a part of the game, some kind of "dick-kick"?