You could also have it go beyond direct references and in the final levels you are suing people based on standard game play mechanics. Does your video game use a controller with 4 face buttons and a d-pad? Lawsuit. Top down exploration eith secrets? Lawsuit.

The final battle: does your game generate random numbers? Lawsuit. Finally, just as Nintendo is about to hold a patent on every game possible you hear the Sega call off in the distance...