The gameplay of No Man's Sky is built on four pillars: exploration, survival, combat, and trading. Players are free to perform within the entirety of a procedurally generated deterministic open universe, which includes over 18 quintillion (1.8×1019) planets, many with their own sets of flora and fauna." - Wikipedia
The above is an understatement. It is also an open universe and open world. It also plays somewhat real time, like how long it takes you to fly to a planet even with your 'Pulse Engine' aka Hyperdrive (as-in Star Trek). Also, as you approach a planet you encounter asteroids that have to be avoided or destroyed with ship weapons. Then there's the enemy starships.
They just released Pathfinder Update v1.20: "The Path Finder update introduces planetary vehicles, Base Sharing, PS4 Pro support, ship/weapon specialization, permadeath mode, and much more. It shows the path for the future."
Base Sharing: "Bases can now be shared online, allowing other players to discover and explore your outpost."
The play goes like this:
- You start with your starship crashed on a planet
- You have to repair your starship so you can take off, which means....
- You have to salvage parts, gather minerals and ores, etc, needed to do ship repairs and upgrades to your environmental suit and 'weapon'
I am really having fun playing it.