Endless runner with high scores and stuff? This is an old concept. There are many games that fall into this category. So what makes Race the Sun unique? First of all, it's endless not only forward, but also to the right and left, which means you can come up with your own route based on where you feel you can collect more points and bonuses. A unique feature I love even more, however, is the mechanism of world refreshing. Basically, every player will have the same world pattern. However, after 24 hours the world is recreated and you need to come up with new routes and strategies if you want to beat your previous record or do as good. That's why daily leaderboards present in this game make so much sense - everyone competes on equal footing, in the same world, yet it won't grow to be boring due to the fact it's only there for 24 hours! The coolest thing, as far as DRM-free goes? These new worlds are not downloaded from the dev servers or anything. You can be totally offline and you will still have a new world generated after 24h - and it will be exactly the same everyone else will have (unless you change your calendar's date, I guess). Last, but not least, there are user-made worlds browsable and playable from the game itself, as well as a world editor.
A small notice, seeing how some reviewers failed to understand - this game does NOT require online connection (and as such, external account registration) for anything other than online leaderboards and user-made content browser. Also, it's important to note that you are given a Steam key for the base game after buying it here - it's important because Steam and DRM-free leaderboards are SEPARATE. If you want to compete with Steam users (Steam leaderboards are more populated), you need to play the Steam version. What's more, whereas a DRM-free version has a built-in custom world browser, the Steam version utilizes workshop for custom levels and, once again, these two are separate.
I would like to write more, but can't