I am the mod and creator of /r/Nuon. The awesome thing is that the subreddit is as big as the device was popular. Please don't go there, I like it as is.
The Nuon player was a line of DVD players that played games and had extra features in movies that were only accessible with the Nuon Player. The Nuon was never popular and likely never will be. There was 4 movies that used the Nuon for extra features. There was 8 games released and one of the 8 was for the Korea only Nuon. The people that bought a Nuon in Korea kind of got screwed if they wanted to play games on it because all they had to choose from is that one game. The only game worth owning on it is Tempest 3000. To give you an idea of how poorly the whole thing was implemented there is one controller that is needed for one game, no other controller will work on that game.
So let's break this all down:
The technology was available to the public from 2000-2003
There was 4 movies that used the technology, They were not popular or even considered good movies.
There was a total of 8 games released.
In South Korea there was one Nuon player released with one game that could be played on it.
Of the 7 games released in Europe and North America, one game game required a special controller that was designed for that one game.
Four of the games that were released on the Nuon were also released on the PlayStation.
There was 3 original games released for the Nuon, Merlin Racing is a racing game that's not very good, Freefall 3050 A.D. (the game that requires a special controller) and Tempest 3000.
There was a cable box that used the Nuon technology that had no way of playing DVD as it didn't have a DVD drive.
Everyone that I have talked to that has played all the games for the Nuon say the same thing:
If the game was released on another platform, play it on that.
Freefall 3050 A.D. is just awful.
Merlin Racing is not very good.
Tempest 3000 is likely the only game that was impossible to screw up, so it's the only good game.
Don't buy a Nuon unless you already have Tempest 3000.
I haven't played all the games for it so I have a neutral opinion on it. The homebrew scene is pretty good. there is a lot that they could have done with the technology if they just tried to do something with it.