They'd have to do something like gate the games behind purchase of a phone-compatible game controller. 2D side-scrollers are great pick-up-and-play short-term

They'd have to do something like gate the games behind purchase of a phone-compatible game controller. 2D side-scrollers are great pick-up-and-play short-term experiences, but they are absolutely terrible to play on a touchscreen. Try the Sonic the Hedgehog demo and see if you can stand it.