His rise in the app store is questionable. He most likely gamed the app store using bots.

His rise in the app store happened after he was featured on a popular Youtuber's account.

A couple of million people seeing someone play your game will tend to drive sales in a way that pushes your app up the charts.

That would I call genius, however questionable it is. For me it feels 90% of people have no other reason to play a challening game than to brag to the other from the 90%. You just need to get into the spotlight.