Not every game needs to have dozens of quests, tiered objectives, and an hour of cut scenes before you get to the actual game. Gathering Sky is a simple adventure game with great music and a casual gameplay style. One thing it doesn't have is in-app purchases.
You start Gathering Sky with a single bird, fluttering on the wind. With the music (by the San Francisco Conservatory of Music) backing the adventure, you set off to find more birds for your flock and progress through different areas. Each one has its own soundtrack as well. The controls are simple enough that anyone should be able to play. Just press and hold and your flock of birds will swoop in that direction.
The graphics are simple but elegant, and there's about an hour of gameplay. That's not a lot, but I feel like this game is more of a playable miniature concert than your standard adventure game. It's optimized for tablets, but a larger phone should work fine as well.