Her Story's mechanic (search engine browsing) requires you to pay attention to the words in the videos, making this game more about watching stuff than anything else. And the reward for paying attention to Hannah/Eve's words, for knowing where to look next? More videos! The fact that the test/reward system loops isn't specifically the point, though it's common to pure payoff games. What I'm getting at is that your actions are rewarded in a very 1:1, organic, makes-sense kind of way, a way that doesn't feel like game mechanics at all, but rather the logical result of your efforts.