The man behind New Star Soccer is getting very rich, very fast. Latest estimates put his income at £5,000 a day, and not many games seem to absorb swathes of my Twitter timeline like this one - especially on smartphones.
I had my period of deep addiction: journeys to and from work, nights that became later than they should, exchanging tips with guys in the office when cramming in a few sneaky games over lunchtime.
And then it stopped. New Star Soccer got too easy.
New Star Soccer proved compelling for a couple of weeks, but its formula became evident and my interest waned: my footballer got too good, I worked out the game's patterns, I earned enough money to buy success and, at just 23, I cleaned up. I started out as FC United and became Manchester City, and fast.
It's not the first time it's happened, with many Kairosoft games suffering similarly. Grand Prix Story, Game Dev Story and Mega Mall Story have all had me addicted for two or three weeks but, just as quickly, they've relinquished their grip on my tube journeys and tired eyes.
The same happened in Real Racing 2 and both Reckless Racing titles thanks to formulaic career modes and in Shine Runner thanks to no career mode at all. It's this lack of end-game, variety and increasing difficulty that sees me lose interest, and this lack of challenge and direction seems to be endemic across a large swathe of smartphone games - even with good the graphics and mechanics shared by every game I've named here.
Does the broader, more casual and less experienced demographic of a significant portion of smartphone gamers mean developers are can afford to make their games less challenging? Do developers think that shortened attention spans mean people don't need long, absorbing games, or are inexperienced developers simply not used to creating smooth difficulty curves and engaging, long-term titles?
I suspect it's a mix of all those things, but I also don't think it would take much to address these issues. New Star Soccer could replace its punishing twists of fate with more variation and Game Dev Story could swap its diminishing, processional latter stages for a trickier and more volatile experience in the second half of the game.
Kairosoft has already demonstrated in its later games that more variety can be added: in planet-hopping strategy game Epic Astro Story there's significantly more to do.
Mobile games, whether on Android or iOS, have something of a reputation for brevity, whether it's Angry Birds bite-sized levels or Draw Something's quickfire rounds. Games like New Star Soccer and Game Dev Story already buck this trend but, with dwindling interest and a lack of variety, it's clear they could do better - and, as both platforms mature, it's clear they will.