Emanuele Feronato has been publishing tutorials about creating his game zNumbers in Phaser: "When I first made zNumbers prototype, I wondered why Karl Barter, the author of the original game, only created 10 levels.
Harware limitations? It was first released on a Sharp Zaurus, so maybe this is the reason. Or maybe Karl decided 10 levels are enough.
Anyway, I decided to code a level generator, and it’s working quite good, I can even choose the difficulty of the level as well as its size."