The fact that a game can actually have people asking what the hell you do is reason enough to avoid.
The people asking "what do you do," as this point are being purposely obtuse. There is a plethora of information about what the game is about, and it's gameplay systems. Mainly because Sean Murray has to answer the same question of "what do you do" in every single interview he gives.
Pick a random interview, and I almost guarantee the answer to questions like, "what do you do?" "Is there multiplayer or co-op?" "How many planets are there?" "Can you craft things?" "Can you mine things?" etc. Eric, are there. It has a painfully simple game loop:
No Man's Sky:
1) Spawn on a planet.
2) Depending on the conditions of the planet, you'll have to prioritize finding shelter to keep environmental hazards like extreme hot or cold temperatures from killing you, or hunting for resources that will upgrade your multi-tool, armor, and ship. Your multi-tool can be used for mining materials and offense.
3) Upgrading your ship will eventually allow you to travel the stars, in a quest to get to the center of the universe.
4) The above goal requires you to venture from planet to planet, starship to starship, collecting, trading, stealing resources from other sentient NPC's to get further and further to the center.
5) Mining planets isn't as easy as it sounds, because disrupting the ecosystem of a planet can bring the robotic guardians down upon you. They police the universe.
6) There are also alien languages to learn. Discovering monoliths and selecting the right option will reward you with knowledge and lite of the Galaxy. That knowledge can increase your rep with the other sentient factions in the game.
7) befriending a faction can reward you with equipment and discounts when trading. You can curry favor through dialogue, or helping out that faction if you see them getting attacked by pirates (or you can piss them off by pirating their resources yourself).
8) During your trek to the center of the Galaxy, you can name the creatures and planets you discover. This information will be uploaded to an online database, so other players can locate your planets and creatures, and share their own.
I'm sure I'm missing things, but that's the overall gist of the game. It's emphasis is on exploration and discovery. The gameplay loop isn't designed for you to stick it out on a planet for 100 hours, but you're encouraged to get off world and find new stuff.
There doesn't seem to be a quest system. Planning your way to the center of the universe is up to you. You'll set your own tasks, and ideally emergent gameplay scenarios is where the fun will lie. I personally enjoy exploration and documenting animals (one of my favorite games ever is Beyond Good and Evil; I was addicted to photographing every species on planet Hyllis). I don't need intense shootouts and epic set pieces, and this game will not be for everyone. My impression is that this game will be for folks that want to sit back and chill for a few hours, and unwind getting lost in a world.
The "what do you do" crowd seem to be annoyed that the game isn't dripping with a ton of gameplay bells and whistles, but the Hello Games team have never been coy about explaining what this game is. From the first trailer, it showed you what to expect. They've sense elaborated on that in more detail, but it is exactly what they say it is. They haven't made any Will Wright esque claims like Spore. They haven't claimed that the game is going to be revolutionary, or teem with complex gameplay mechanics and dripping feature after feature. It's always been a game about exploring and discovery. Some people can't accept that. They seem to feel that a game of its scope almost demands that it be more than just waking around a planet and collect resources, that there's just GOT to be more to it! But it's always been what it's been.