As of iOS 9, the Apple Watch's platform already got an upgrade with watchOS 2. The Apple Watch is generally, at the moment, not a video game platform. Without taking the small screen size into play, apps made for the Apple Watch don't have much in the way of making game-like graphics updates. In the future, this might change. At the moment, apps made in watchOS are like child apps of main iOS apps. Eventually, we can make watchOS apps separately without having them attached to a parent iOS project. However, some developers have made simple text-based games for the Apple watch. It's possible that in the future, we could make more action-oriented games for the Apple Watch.

Currently, it's very much possible to make a game that uses the watch for accessories data, such as inventory, maps, and more with a little bit of ingenuity. One feature of the Apple Watch that we could design games or game controls with is Force Touch. Force Touch senses how firm the press gesture is. This isn't something new to game design as a whole but new to iOS with the next line of iPhones and iPads most likely having this feature as well. Getting the strength of a player's touch and taps could allow some intuitive gameplay mechanics for the next line of mobile games.

For more on the watchOS to possibly inspire some game development ideas for the device, check out the watchOS 2 preview page at https://www.apple.com/watchos-2-preview/.