I read a one sentence review that said, "No Man's Sky is miles wide and an inch deep." I think that is the main issue with the game. You are given and endless expanse of nothing to do in it.
I enjoy the freedom of doing whatever I want but that isn't what the game is. You are actually very limited. You're not building structures or creating a base, or building a ship, you are wandering lost everywhere gathering resources. You sort of create and trade things in your inventory but it doesn't make you feel grounded with a goal and an understanding of what you're doing. Some say it's a survival game, but does that mean if you can maintain all your shields and systems then you've won? No, of course not. You are supposed to feel a drive to explore and find more of what is out there. But the game doesn't tease you that there is more out there. For me after visiting three planets I see pretty much the same things and I'm doing the same tasks. In a game where they say you'll never be able to see it all, seeing it all really isn't a goal you try to achieve. So is exploration the goal??
You start the game with a crashed ship and use raw materials to "fix" it. An amazing feat. But for a character with the ability to do vast space exploration it feels strange to not know anything about where you are and where you're going. You feel like a super smart infant with no clue of the world they inhabit. To make me care about what I'm doing I'd like to know who I am. You are a lone what? Human? Nothing really tells you that. Every intelligent life form you encounter is described as an alien. But you have a fancy ship and fancy tools so where did you come from? Are you a part of something bigger? Have you just lost your memories? Did that question matter to the game's creators? What the hell is the premise of what you are and what you're doing?
I also theorize that the game might be too open for people to easily grasp and in some cases myself included. Many people need at least a little guidance . Looking at the Elder Scroll series from Morrowind to Skyrim you can see Bethesda tightening the reins on the amount of hand holding and still some people found Skyrim too open and don't know what to do with themselves. I loved Morrowind and hated the more guided direction of Oblivion and Skyrim but No Man's Sky give you nothing at all.
I'm going to continue with No Man's Sky for now. Maybe the game is exactly what I've seen and nothing deeper but I can't shake the feeling that I just haven't figured it out yet.