Answer: The 64DD
When Nintendo throws you out of the park, they really send him to the moon. The original NES system sold nearly 62 million units worldwide. Their successor to SNES sold over 49 million units. Even obscure iterations and special editions of their Game Boy series sold millions of times.
When they are hot, they are hot. If not, it is painful. While many of us remember the marketing disaster that was the Virtual Boy gaming headset, the fact that we even remember the Virtual Boy means it was alright (even for a flop). The headache-wrenching Virtual Boy still managed to deliver around 800,000 units worldwide. Outside of collectors and video game fans, however, hardly a soul has heard of the unfortunate 64DD.
Although the 64DD, an add-on for the Nintendo 64, was already announced before the N64 itself brought the product to market for years in the development phase. The add-on promised advanced game features, including magneto-optic discs, online games, and a host of other features deemed damned innovative when the N64 was released in 1