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All the old blog posts, written from 2008 to 2017

PhoneGap App Highlight: 0h n0

0h n0 is a lovely little logic game built with PhoneGap and just won a People’s Lovie Award for mobile gaming! The app is available on Android, iOS, Windows, Chrome Web Store and also on the web.

How do you play?

0h n0 follows three rules:

  1. Blue dots can see others in their own row and column
  2. The numbers on the dots indicate how many can be “seen”
  3. Red dots block the view of the blue dots

It’s up to you to complete the grid using the numbers as a guide. Simply tap a tile to make it blue or red and complete the grid. 0h n0 gives you unlimited puzzles for many grid sizes.

Each puzzle can be played in perfect Zen mode without any pressure. Or you can challenge yourself by attempting to beat your personal best time in the game’s time trials, unlock fun achievements and compete with friends in leaderboards.

Technical Overview

0h n0 was built by Q42 using the same vanilla javascript engine that we used to launch its predecessor 0h h1. Both are available on GitHub if you want to see how they were built specifically:

With each game release we wanted to learn and experiment with something new. At the beginning we learned things like how to write your own PhoneGap-like wrapper with our game Quento, playing with Unity and creating a premium paid app (Numolition) and creating a ridiculous April Fool’s game for nerds (Flippy Bit And The Attack Of The Hexadecimals From Base 16).

For 0h we went completely free. That meant:

  • a free game
  • no nagging 3rd party ads
  • no free-to-p(l)ay mechanisms

0h h1 became a pretty big hit for us, so with 0h n0 we wanted to experiment with the next thing: achievements and leaderboards. We consider ourselves lucky that we were able to cherry-pick the right PhoneGap plugins to implement this feature on iOS and Android and enhance user engagement and retention. The difference was exponential! Never did we expect 100,000 sessions to be played each month across all platforms. That’s over 3,500,000 puzzles completed since launch! But what’s even more fascinating is the fact that some fans managed to finish 15,000 puzzles single-handedly (and even 30,000 puzzles of 0hh1).


Logic games don’t require any visual brute force to make them engaging and fun to play on a daily basis. HTML5 and PhoneGap were the perfect choice for taking the app from game prototype to a released app with thousands of enthusiastic players.

Thank you PhoneGap team!