I burned out after 100%ing it and beating A20 on all chars, and haven't been able to really play in a couple of years, but I got every penny of my investment back and more.
My son has it on his phone and he plays it waiting for toast to finish, at halftime of soccer games, in the car going somewhere...
Yeah I stopped for a few months after I finally got my Silent A20, but once it released for Android I picked it back up. It was the last achievement I needed for Eternal One. It feels great on a tablet as well.
Such a good game. I almost never played it just cause I irrationally didn't like the name. Glad I picked it up.
Usually ones that come with an upfront cost, but yeah. There's actually a lot that are pretty good, like Monument Valley 1+2, or Stardew Valley's mobile port.