Fully immersive quests in which your choices determine which adventures you experience. Level challenges could be avoiding obstacles, defeating opponents, collecting things, etc., all on the way to a portal that will unlock your next choice. Adventure ideas include: a knight on a quest, a kid exploring the ocean, prehistoric dinosaur adventure, a mythical magical land, a ninja mission.
Example: You’re a knight on a quest. You can choose to go through the forest or climb a mountain. If you go through the forest, you collect berries (but not the poisoned ones!) while avoiding dangerous wildlife (branches and bears and bats, oh my!). If you go climb the mountain, you have to avoid the falling rocks and birds that are flying by.