Really, nobody comes out of this one looking particularly well.
No Man's Sky is a mediocre, so-so-ish game. If it had been a $25 indie title that slipped out quietly, it would probably have had a pretty decent reception. But it was hyped, by a developer who appears to want to be the second coming of late-career Peter Molyneux, to be a game that was both fundamentally different to and better than the game that was actually released.
But the people asking for refunds after putting a serious amount of time into the game are also kinda jerks. Digital-purchase refunds have come on a long way in the last couple of years. Weirdly, we have EA to thank for this, as they were the first major party to take the plunge on it, via Origin (hey, credit where it's due). But refund policies set sensible limits. If you've put double-digit hours into a game before deciding you want a refund, you are probably doing something wrong. What's more, the gap between expectations and reality with No Man's Sky was widely known within 24 hours of release. If you got stung because you pre-ordered... then for the love of all that is holy, stop pre-ordering.
And a special de-merit here for much of the gaming media. Quite a few outlets have put more time into defending Hello Games, because gamers are angry with them (boo! hiss! angry gamers! they must all be sexists!) than they have taking them to task for some seriously deceptive marketing.
I did buy it myself. A week or so after launch (so I knew full well what it was like), I managed to get a fairly cheap PC code via cdkeys.com. At the greatly discounted price I paid, the game is more or less worth the money. I put 12 hours or so into it before I got bored and moved on. Mods might add some value to it in time. But I don't feel the need for a refund.