With the exception of Dragon's Dogma and Dark Souls, games don't generally do dark well. The night sky isn't blue, Ubisoft: it's black, and you can barely see a few feet ahead, or just slightly further with the aid of a torch. Reaching, however, is a game about exploring in the dark, in the actual dark. A game about stumbling from one infrequent light source to another, and trying to memorise the geography of a cavernous ruin.
It's a bit barebones, and I think more could have been done with the sound design to create a richer atmosphere, but what's here is interesting. You're trying to get to the end of an almost completely dark space, while only being able to see a small area around your feet. Helping you out are scattered lights, which serve as lighthouse-style beacons, but that also allow you to activate them with a left click.
Activating a light will cause waves of light to ping out in all directions, revealing an extensive section of the cave. You can see every pathway, every narrow walkway, every wall. But only while you're standing next to the light. Sooner or later you'll have to leave it, and try to remember the shape of the world as you gradually guide your character around.
It's an interesting mapping challenge, in a world with an element of mystery, and a bit of atmosphere. All you can hear are your own footsteps, as they echo in the ruins of this vaguely ominous, empty, pitch black world.
For more great free experiences, check out our roundup of the best free PC games.