No Man's Sky is an epic adventure, waiting for you to decide what kind of adventure it is. You play, from a first-person perspective, as a space pilot who navigates the game's enormous universe, numbering quintillions of planets and similarly uncountable numbers of species, characters, and music, all skillfully generated by the game.
The great expanses of space
Whether you drink planets dry and kill their inhabitants, trade peacefully and learn about species you never knew existed, or simply get by from day to day, the game will accept the decisions you, the player, make unquestioningly. Whatever you decide to do, however, the game probably has mechanics that make it engaging. The economies of individual planets, the resources they offer, and their inhabitants can all fluctuate based on the actions of other players... and you're counted among that. If you shoot down too many hapless beasts, or strip-mine half of a planet, then the game will most likely send some sentinels down from space to give you a real fight. You might discover a blueprint for a new ship, only to have it destroyed in battle after you've built it. The game is what you make of it, but it gives you a LOT of food for thought.
A sky for one person alone
At first brush, No Man's Sky may appear to be a multiplayer game, but reality is more complex. The game can be played offline, so long as you're online long enough to receive things like planet coordinates and data updates.
And while multiplayer is a feature of the game, two players can navigate an entire planet, if they somehow manage to end up landing on the same one, and never meet each other. Two players might talk to the same characters, and leave indelible marks on that planet... but it is unclear if and how they are able to directly interact. As many online games do, NMS will change over time, and the multiplayer features may become more and more fleshed out.
Still, regardless of how many other players you might one day meet, space will by and large feel very lonely. You'll rocket past uncaring stars and name planets no one else has ever touched. You'll discover species unique to those planets, with features that manage to mimic nature in spite of being procedurally generated. Above all of this, the game's graphics are breathtaking: they're high-end, and the game makes them count for every shred, every polygon. No Man's Sky may be lonely, sometimes dark, but it is never ugly... unless one of the species is.
A banquet of the stars
Well, what's there to say in this summary that hasn't been said better in the rest of the review? No Man's Sky is a lonesome multiplayer experience, an unparalleled game full of exploration but with nothing you've been planned to find. It is a huge, wide open sandbox full of conundrums. If it seems worthwhile to you... then you absolutely must play it.