Xmen vs sf , Marvel vs sf, vampire savior, etc., Those all came in two different forms. If it came in a big cardboard box with the ram, it wouldn't have a back cover becasue the back cover is the actual box art. If you got the version where you just bought the game without the box/meg cartridge then you would've gotten a regualr back. Chances are the guy you bought it from either kept the ram/box for himself, or he bought it used and never had one