I like Dungeon Quest. A fast-paced, randomized little action RPG (think Diablo 3 extra-lite) with only the barest of microtransaction fluff (costumes). Plus, randomly generated loot! This, something Diablo realized in 1998, will keep people coming back forever.
Use the on-screen stick to zip your little guy around, whacking enemies and collecting loot.
Dungeon Quest is also the name of the board game that got me into RPGs over 20 years ago. You would march around little plastic guys, roll dice to beat up skeletons, and get treasure from heavily-guarded rooms. Two decades later, and we’re doing that on our pocket-computers while waiting to pick up our kids from school.