Flow is more-or-less a game based on an academic paper. To be more specific, it comes from Jenova Chen’s thesis which discusses applications of Csikszentmihalyi’s “flow” theory to gameplay.
The simplest version of the theory is something like this: we enjoy activities that challenge us, but aren’t so punishingly hard that they’re frustrating. Games should “ramp up” difficulty in response to player skill, so that players stay in the “flow state” of constant challenges that are just out of reach.
The game itself is almost startlingly simple. You’re a little swimming creature. You can eat smaller things, or get eaten by bigger things. As you gain skill with the controls, the “level” you’re in seamlessly changes to get harder and harder, introducing new harder-to-avoid microbeasts. Once you progress far enough, you “level up” and become a new, more-complicated organism.
The ethereal visual elements and sound design lend to an extremely relaxing experience. If you ever need to de-stress, this is a good way to do it with a game (vs., say, gunning down 11-year-olds in Call of Duty).
The game is also very easy to understand, and quick to play, so it’s worth a try. There’s a free web browser version available, so you really have no excuse!
You enjoy relaxing games, or are interested in seeing a particularly focused implementation of difficulty curves that match player skill