"The Generation NEX is built around the Nintendo-on-a-chip technology or NOAC as it is commonly called. This is an attempt to fabricate the original NES hardware on a single computer chip. The technology is not perfect in that it does not fully imitate the hardware perfectly. But the method is cheap to make and mass produce. Some, or many, manufacturers have taken advantage of that. Over the years there have been literally hundreds of NES clone systems built around the NOAC. I am led to believe that in recent years NES patents have ran out and this is the reason we are beginning to see many NES clones hitting the US market place and being legal. Before you had to import things that were a bit on the shady side and illegal. And a lot of times of a very cheaply low quality build. "