I have a great deal of respect for this guy. His business decisions in the early 80's literally saved the video game industry. He took the risk to sell a game console in the west when the market had completely fell out and once the NES did take off he instituted a iron clad "only x games per company per year" policy that prevented a repeat of the 2600 and it's rampant shovelware.
Also he took over the company in 1945, yeah right after WWII and managed to keep it successful. Not only that, but in the late 70's he had the vision to shift the focus of the company from card and board games onto electronic games. That takes some serious smarts. Imagine if Milton Bradley, which was a wildly successful company in the 70's, had decided to abandon their board games and start making video games. That is the kind of risk he took.
You can also partially thank Atari's misstep for what Nintendo became. They were approached to distribute the NES in America at first but blew the deal over a misunderstanding of licensing rights of Donkey Kong (which was being displayed on the Coleco Adam when Atari had "home computer" rights.) I shudder to think what the industry would have become had Atari handled Nintendo's hardware.
But don't want to take away from Yamauchi's legacy. It was under his leadership Nintendo forged ahead anyway with some brilliant marketing strategies that worked. We wouldn't have what we have today if it wasn't for him and Nintendo revitalizing the industry.
And speaking of Milton Bradley - don't forget they also released the Microvision, one of the first portable games with interchangeable games. They were still doing board games mainly though. And as far as NES games - yeah, as Howard said, they merely published them. (e.g. Marble Madness, an Atari game; Captain Skyhawk, a Rare game, etc.)