Don't Rest Your Head, by Fred Hicks of Evil Hat Productions, is a game of people that have fallen between the cracks into a world of insomnia and madness.
You are playing someone that has been awake so long that they have gone insane, or woken up to finally see the hidden truths in the world. The Awake can interact with the lost and forgotten parts of our world, using them to gain access to the Mad City - a dark place home to Nightmares and occasionally other Awake trying to follow their path.
Creating a character in Don't Rest Your Head involves little in the way of mechanics and is mostly about defining who you are, who you seem to be, what is driving you and where are you headed. The trajectory of a character is by far the most important aspect - it is your velocity and your direction. It is why you are in the Mad City, which isn't really somewhat that you want to be (if Dark City and Wonderland had a horrifying child, it would be the Mad City).
The Awake draw power from their exhaustion and madness, using them to fuel their talents. Every character has an exhaustion talent, which is mundane in function, but allows you to go far beyond human norms, and a madness talent, which is just straight up magic. Exhaustion talents can be anything from incomparable acrobatics or driving skills, to the most interesting man ever. While madness talents are in the vein of teleportation being so well prepared that you can retroactively say that you have something you need. Using either of these requires interacting with the dice mechanics, which is the meat of the system.
Every time you pick up the dice, you are making a meaningful decision. The outcome of that roll is going to have consequences; they can be good, but let's face it, even if you succeed they are probably going to be not so good. Mad City is a brutal place. Helping you succeed against the GM's pool of Pain dice are your strange new bedfellows: Exhaustion and Madness. These can be drawn upon to supplement your natural discipline, but not without cost.
Exhaustion increases are cumulative, each die adding to your pool. As your exhaustion grows stronger, so do you, but so does the danger that you will fall asleep. When that happens, you are at the mercy of any Nightmares that happen upon you. Madness gives short bursts of power, lasting only for the test, including activating your super power. Drawing on madness always leaves you with the chance that you can snap - forcing you into fight or flight. Snap too many times, and you become another Nightmare in Mad City.
Within the Mad City are strange and impossible places, along with the equally strange and impossible Nightmares that call them home. You should be aware, they are all puns; if the thought of the terrifying embodiment of bureaucracy being named the Tacks Man, with his minions the Pin Heads and Needle Nose bloodhounds, makes you groan, it may be a good idea to stay away. Regardless, the setting and its inhabitants are evocative and inspirational for a descent into madness in a familiar, but alien world.
There is a lot in Don't Rest Your Head that shows its relation to Fate games. The Despair and Hope coins that move between the GM and players are a prime example and similar function to Fate points. If pain dominates in any roll, the GM gets a Despair coin to make the player's life that much more difficult. When it is spent, however, it turns into a Hope coin which allows the player something of a reprieve. A similar relationship exists between Scars and Aspects, the former being the closest that you will get to advancement.
The strong direction of the game and the atmosphere it presents are fantastic for a limited story arc, though may have issues when it comes to longer play. It is also best suited for a one-on-one game (often referred to as a "duet") and struggles with more players present in the game. When more than one character is in a scene, only one is the actor and all others are supporting them. It is, by design, a lonely game. To be fair, a significant degree of ambiance comes from the unknown - can you trust anyone? With other players, there is an implied level of trust and willingness to work together, which can run counter to the stories that Don't Rest Your Head is trying to tell.
If you are looking for something with an engaging and meaningful mechanic, particularly for very small groups, and a dark and unique setting, this is going to be a strong choice. Even if that doesn't sound like a recipe for success, the design choices are different enough to warrant further investigation.