I bought a Genesis from a used game store a few years ago and it came with a copy of Streets of Rage 2 (Not for resale version). When I put the game in and turned on the Genesis, the title screen for Herzog Zwei came up and needless to say I was confused as hell.

I finally got some gamebits the other day and opened up the cart just out of curiosity, maybe see if someone left an April Fool's note inside or something, but I don't really know what I was looking for. The screws were very stiff though, as if the cart hadn't been opened before.

Was this probably just some guy swapping out the boards or is there ever a legitimate way this could happen, like in the factory?