The tiny screen and compact processor required simpler animation, which meant scaling back the game's trademark trivia wheel. And some things, such as pop-up ads that help make phone apps profitable, weren't possible when designing for the watch.
               
Designers, including Cavazzani, are generally optimistic about the possibilities of the new watch, the first product developed under Chief Executive Tim Cook, but many are finding that designing for tiny screens requires a new approach.

Just as the development of apps has been crucial to the success of Apple's iPads and iPhones, the Apple Watch's popularity, and ultimately its sales, will depend in large part upon the apps outside developers come up with to expand its usefulness.
               
"You can do some cool stuff, but of course it has limitations," Cavazzani said, and making money "is a little bit complicated if it's not a paid app - there's no way of putting ads and no way to do in-app purchases."
               
Apple has touted health and fitness tracking, communication and style as the chief reasons to buy its wearable, but games are some of the most lucrative apps on the iPhone.
 
Of the more than 5,600 apps created for the timepiece so far, about 10 percent are games, compared with 20 percent of iOS apps overall, according to App Annie, a mobile analytics firm.