Mobile gaming can be a lucrative business. Swedish developer King’s Candy Crush series generated over $1 billion in sales last year alone – an average of $4 million a day – while Niantic’s smash hit Pokemon Go brought in an estimated $2 billion in 2017. Some games  have become entertainment properties in their own right, spawning merch ranges, licensing deals, brand partnerships, and blockbuster films (remember Angry Birds?), as well as hundreds of millions of downloads.

But with over 900,000 games on Apple’s App Store, there’s a wealth of competition, and for every viral sensation, there are plenty more games that fail to take off. As with any industry, success is far from guaranteed, and some of the top games of the past few years have seemed an unlikely sensation.

So how do you create a game that will get people talking – and, most importantly, playing?