We have eagerly followed the news of the new mobile OS of Mozilla right from the start, thus when our friends at iMind helped us to a Keon mobile, we immediately decided to develop a simple game app for it as an initiation.
We choose the dice game Yatzy, which was familiar to many of us and enjoyable alone as well, like solitaire.
We finished the game in a matter of a few days. It is available on the Firefox market, playable in the browser, and its source code is available on Bitbucket.
The app was developed with the help of a simple browser (not even Firefox, but Chrome). At certain points, I checked the result on my phone, but I hardly met an error.
Finally, the app received its (almost) final look from trn - later, this had to be simplified a bit as the phone's browser handled shadows and tints with difficulty.
In our experience, app development for Firefox OS takes only a manifest file more compared to the development of an average mobile app. Naturally, if we want to have access to sensitive data (e.g. phone book), then we must meet slightly stricter requirements, but none of these is impossible—and, as always, the Mozilla Development Network provides a huge amount of help.