Released in 1976, Mattel Auto Race became the first widely popular handheld video game. It was developed by Rockwell International for Mattel, which wanted to try its hand at converting a calculator into a game.

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By 1977, Mattel had released a number of handheld video games, including what would prove to be one of its most iconic: Mattel Football.

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The Monte Carlo game watch may be the first example of a game programmed into a wristwatch. The watch included three games: jackpot, dice and roulette (according to the December 1977 issue of Popular Science). To play, the watch owner pushed the button and the display showed the results of the game.

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Like the Monte Carlo, the Slot Machine watch used a generic watch face and randomizer to create a game.

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Inspired by seeing someone playing with a calculator on a train, Nintendo's Game & Watch series of LCD games became wildly popular first in Japan and then internationally. The first was Ball, which had players controlling a juggler. Nintendo discontinued the Game & Watch in 1991.

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Casio's sudden interest in game watches seemed driven by the company's desire to create a wealth of nerdy, seemingly impossible timepieces. The GM, or game, line kicked off with the GM-10, which featured a tiny rectangular play space and a game that had you trying to shoot down a spaceship with your rocket. It is now among the most valuable game watches on the market.

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By 1981, Nelsonic Industries, a company known for its pop culture-themed watches, got interested in the game watch market and began to produce a number of well-known game watches. Among its first was the Nelsonic Space Attacker.

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With the growing popularity of not just the Nintendo Game & Watch titles, but the slew of other "calculator games," GCE hired Western Technologies to design a game watch, never mind that no one on staff had any experience. The Game Time became a massive hit because it featured four games on one watch. It also led to the release of the GCE Sports Time and Arcade Time.

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In 1982, Nelsonic released one of its most popular game watches. The Pac-Man watch sold for $25 to $35, and was so popular that it was re-released with multiple faceplates and even in a version with a small physical joystick. The company sold more than half a million of the watches.

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As Casio slowed its production of GM game watches, it decided to release one more: a throwback to the company's popular calculator game Digital Invader. The game, now on a calculator watch, had you typing numbers to halt the steady advance of number-shaped aliens on your watch face.

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In 1989, Nelsonic managed to lock in a licensing deal with Nintendo to produce game watches based on some of the Japanese company's properties. The first of these was Super Mario Brothers. The company went on to release Nintendo-licensed watches for Super Mario Bros. 2, Super Mario Bros. 3, Super Mario World and Super Mario Kart, as well as Tetris, Star Fox, Donkey Kong and The Legend of Zelda. None of these games were particularly well-received by critics, but many of the watches sold well. The last of these watches, Donkey Kong, was released in 1994.

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For all intents and purposes, Nelsonic's 1994 Donkey Kong watch ushered out the video game-themed wave of game watches. While occasional watches with games on them popped up here and there, they mostly stopped being produced. Then in 2003, Fossil delivered something amazing: the wrist-based personal digital assistant. Work began on the Fossil Wrist PDA in the late '90s, but the product wasn't seen as viable until the release of a tiny, touch-sensitive screen in 2002.

The Wrist PDA was able to include most basic PDA functions, like handwriting recognition (used with a tiny stylus tucked into the wrist strap), a calculator, a to-do list, memos, datebooks and, yes, even some games.

Among the games available on the monochromatic $250 Fossil Wrist PDA were Karateka, Farkle and classic text adventure Colossal Cave Adventure.

Microsoft's first major foray into smartwatches started with the SPOT, or Smart Personal Objects Technology. The idea was to create a technology that used FM broadcast subcarrier transmissions to distribute data to "intelligent" home appliances, consumer electronics and watches.

While a bit of the tech leaned on an idea first used for distributing games on an Atari console, the SPOT watches didn't actually support any games. Instead, the watches were able to deliver bite-sized bits of information wirelessly via FM broadcast. Fossil, Suunto, Tissot and Swatch all released watches using the tech, which allowed owners to check news, read and send emails and send instant messages.

While packed with innovation, SPOT failed commercially, and the MSN Direct service that supported the devices was shut down in 2012. The idea of smartwatches seemed once more to die.

In 2009, South Korean company Samsung unveiled its second run at a watch phone. The S9110 was designed to be a standalone device that could serve as both a phone and, in a limited capacity, a personal assistant. It included a touchscreen, voice recognition and a music player, but no game support at launch. A slew of Java games hit the device later in its life.

These days, Samsung is more interested in making devices like the Gear and Gear 2.

Image source: Samsung press site

The Sony Ericsson LiveView was designed to use the Android platform to help people get the most of their phones. The device was a tiny square OLED display that came with a belt clip and watch band. Among its many features was the ability to control your music player, read texts and RSS feeds, check out Facebook and Twitter, and, most importantly, download apps from the Google Play store. Not only did that include games, but people quickly took to modding the little display to allow it to, among other things, run a Game Boy emulator. An improved LiveView 2 hit next, followed by the Sony SmartWatch in 2012.

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Before there was Pebble, the massive Kickstarter success that launched a new sort of smartwatch, there was the WiMM. The smartwatch was to run Android with a custom user interface; it included a high-power color screen that could switch to a low-power grayscale mode, as well as a built-in magnetometer, accelerometer and Bluetooth connections. The idea was that the device would ship out to developers who would then help seed a Micro App Store for the device, which would later go on sale to consumers. But that never happened. Instead, Google snatched up WiMM Labs, absorbing the company and its innovative little watch into Google's own smartwatch plans.

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The Pebble Smartwatch made history in 2012 when the Kickstarter for the watch raised $10.3 million in a bit more than a month, a record at the time for Kickstarter. The Pebble watch boasted a grayscale screen, nearly a week of battery life and compatibility with both iOS and Android devices. It also incorporated a magnetometer, light sensors, accelerometer and Bluetooth, and was waterproof.

The Pebble Store boasted more than 1,000 apps by early 2014, among them plenty of games, the watch's most popular sort of app. A heartier Pebble Steel was announced in 2014. In 2015, Pebble announced its follow-up to the original watch: the Pebble Time, which has a color screen. Steel and Round versions of the Time were later announced.

The Omate TrueSmart is another Kickstarter success story. The smartwatch raised more than $1 million in about a month. Unlike the Pebble and many other modern smartwatches, the Omate is a stand-alone device that can make and receive calls and uses its own SIM card. The Android watch also includes a magnetometer, accelerometer, microphone, speaker and camera. The device can run a limited number of specifically designed apps; there are games, but not many.

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In 2014, Google threw its hat into the smartwatch ring in a big way. The company announced Android Wear, an operating system designed specifically for smartwatches. Asus, HTC, LG, Motorola and Samsung all rolled out supported watches.

The first wave of those watches shipped through 2015. A second wave of watches was announced around the annual Mobile World Congress in Barcelona, along with news that the new watches would also include limited iOS support

When running connected to an Android device, Android Wear watches have a plethora of games, perhaps the most robust selection of any wearables currently available.

Apple finally announced its long-rumored Apple Watch on Sept. 9, 2014. The smartwatch began shipping in April 2015. The first version of Apple's WatchOS included a number of restrictions that hampered some efforts to get robust games on the device.

But with the September 2015 release of WatchOS 2.0, and its ability to allow native apps, that seems to have changed. While there are a number of games currently available on the watch, it doesn't match the quality or quantity of those on the iPhone.