They say that going solar-powered is a cheap and efficient use of renewable energy. Solar-powered endless runner Race the Sun is the most cost-effective it'll ever be, but for today only. Like the game, it's over when the sun goes down.
Developer Flippfly has made Race the Sunfree on Steam today. The gratis offering comes hand-in-hand with the game's (paid) release on iOS. If those platforms aren't really your thing, it's also available on PS3, PS4, and PS Vita -- the latter of which isn't really Sony's thing.
Race the Sun, like all endless runners, has a bleak premise. All you need to do is survive as long as possible until inevitable failure. The game ends when the sun goes down, as your vehicle is powered by the sunlight. Alternatively (and more frequently), it ends when you collide with one of the many, many geometric shapes between you and the setting sun.
What keeps players coming back is the wonderful sense of progression. By ticking off objectives, Race the Sun increases your level and changes the game while doing so. You'll notice the difference almost immediately, as it gets easier and more complicated (but in a good way). It helps that the minimalist style is gorgeous to look at.
If you pick this up, you won't be alone in your futile endeavor. In a statement to Polygon, Flippfly said that the PC version has been downloaded more than 200,000 times. That's a lot of people racing the sun, and far more frustrating crashes long before that giant fireball disappears.