I played Sproggiwood on PC but it started as an app; might be worth a try. There was another rogue-like app I used to like but I forget the name. It was space themed and must have been free (since I mostly use free apps). Zoombinis (which started as a PC game years ago) also has an app now, but I got it mostly for the nostalgia and I'm not sure what age groups would enjoy it. Lastly, I'm not sure exactly what Mystic Messenger is or even if it's appropriate but some of my friends like that.
Good luck!