OK, so I have here a copy of Duke Nukem for Genesis. This game was released ONLY in Brazil by TecToy and it's damn hard to find. Here are some pics:

In Brazil Genesis is called Mega Drive (like Japan and Europe), but carts have Genesis shape AND WILL PLAY IN US GENESIS CONSOLE (I play this game in my Nomad).
I really don't have a price in mind, so just shoot a PM with an offer.