I'll introduce this with a story. This story goes back to when I was in elementary school. You have to know that, at the time, I was allied with Nintendo — these were the days when you needed to either love Nintendo or Sega — and failing to choose between them was blasphemy. So imagine how excited I was when I discovered that my breakfast cereal (I can’t remember for the life of me which one it was, but it was probably something disgustingly sugary) announced loudly via the back of the box that I could send away for a Donkey Kong watch — one on which you could actually play the game. This was not too long after the release of Donkey Kong Country and the rerelease of Donkey Kong for Game Boy, and thus Donkey Kong was very cool at the time. Add this to the fact that I had a good friend with a Star Fox watch, of which we were all very jealous, and I decided that I needed this watch.
So I sent away for it, and the watch came back, and I was very happy. It wasn’t the original Donkey Kong, but I didn’t mind. It was made to look like one of the levels from the Big City world in the new Donkey Kong rerelease, and it was quite fun and challenging. The level repeated and the speed increased if you beat it, and it could be quite a timewaster. Imagine my distress when I lost the watch within the year. It was terrible. I believe I nearly killed a friend a year or two later when he acquired the same watch by finding it in a drawer in the house he’d just moved into.
This watch was one of dozens of watches that the Nelsonic company made. Here’s as near as I could find to a complete list:
The watches had liquid-crystal displays along the same lines as the Game & Watch series and Tiger handhelds. That is to say, they had a background picture painted into the watch’s screen, and a number of outlines of objects and characters that could be turned on or off in such a way as to simulate movement. What this ended up meaning was that the watches could be produced very cheaply but still provide a respectable gaming experience.
The controls for most of the game consisted of up, down, left, and right buttons. Their exact use changed from game to game — for example, in Donkey Kong, up was used not only to jump but also to swing from the rope suspended in one part of the level. Less frequently, games had other control schemes — Pac-Man used a miniature joystick, which came with four different caps of different colors (in fact, the colors of the four ghosts) which could be screwed on and off of the tiny joystick to customize the watch.
The watches were made throughout the 1980s and 1990s, and although most of them were licensed from Nintendo, there were several (see the above list) licensed from other companies and with other themes. Nelsonic was making other watches as well at the time (and still does today), but they will most likely be best known for their game watches, as these are the only thing that Nelsonic has ever made that will become collector’s items. Today, the watches sell for several times their original cost at places like eBay, and it’s well worth your while to pick one up and impress all of your nerdy friends.
UPDATE UPDATE UPDATE! My girlfriend managed to procure for me both a Donkey Kong watch and a copy of Earthbound, and gave them to me at the same time! I have Everything to thank for this — had I never joined, this would never have happened. Thank you all. (and thank you, Kelly — I must remember to propose to you one of these days)
Secondary Update: she said yes.
Source: http://www.handheldmuseum.com