I recently pulled my Genesis out of the attic (I know, horrible place to put it). Sonic 1, 2, 3, Knuckles, and Virtua Racer all work. However, my Sonic Spinball and Adventures of Batman & Robin do not. I've tried cleaning them using a cotton swab dipped in alcohol. Both before and after, it just showed "Produced by or license from Sega" and then went to black.
It's obviously not my Genesis as it works with my other games. Not really sure what else to do.