Point and click adventures are awesome (Day of the Tentacle remains an all-time favourite), and they seem to be under-represented in the mobile game market. This is surprising, given that a touch screen seems custom-designed for the kind of interactions they require. So writing a point-and-click adventure (or perhaps that's just a 'tap' adventure on a phone) seemed like the obvious thing to do.
When it came to the story, inspiration came from my daughters - and specifically, my youngest daughter's obsession with fairies. She desperately wanted to be visited by a real fairy - not something I could arrange in real life, but if seemed like a pretty good premise for an adventure game, and so Leila and the Little Folk was born.
Writing an adventure game added a whole load of new requirements to the game engine.
Adding these things into the engine was only part of the story. Now that I had a game that I actually wanted to build, there was a LOT of work to be done on building the content of the game itself.