The battle cry of people on various gaming forums is "Sean Murray lied!" or "No Man's Lie" or some other variation on that. But were we lied to? People are using the words "promise" and "lie" quite a bit when talking about this game, but those words carry a lot of weight.
There are features missing from the game that were shown or discussed before launch. I chose the video above because it shows portals, something that people were looking forward to, but didn't make the cut. You can find portals in the game, but they don't do anything at all. People have pored over the game files, and there are still references to what might have happened, but as it currently stands they don't function. This, along with many other features, were cut for some reason, including but not limited to: true ship class differentiation (instead of just a bit of a speed/health difference), different resources and climates depending on the distance from the sun, highly varied alien structures, and of course, multiplayer.
For some reason, multiplayer is the one people focus on the most, so I'll go more in depth. Yes, Sean Murray said multiple times in multiple interviews that you could run into other players, but the chances of it were incredibly low because of the size of the galaxy, and in one instance said that if you saw someone you wouldn't know if they were an NPC or another player. But as we know now, two people who happened to be streaming on Twitch ended up in the same place at the same time, and couldn't see each other. An examination of the game files shows no capability for that kind of thing at all-- the only network communications are for uploading your discoveries and seeing other people's discoveries.
Now, I don't understand the hate over this one specifically. Maybe it's just my taste in games. But if you would have no way of knowing if it was another player or an NPC then I don't see it as being a huge issue that it was cut. (However, the current state of NPCs wouldn't allow that either, because they're always behind a desk or manning a trading post, so that's another thing that was cut back.)
So yes, plenty of things were discussed that didn't make the cut. But that happens regularly in game development. We've had years of build-up, so things are expected to change. The question is, what was promised, and were we lied to?
If I make plans to come over to your house for dinner, is that a promise? If I have to cancel because of a flat tire or something unavoidable came up, did I lie about those plans to begin with? I would answer no to both. Planning something isn't a promise, and breaking those plans isn't retroactively lying. It's not a lie if you believe it to be true. However, I would definitely give you a heads up that I wasn't coming so you wouldn't expect me and I never show up.
I think that's the big failing of Hello Games here. It's not that things were cut, it's just that there wasn't enough notification about the changes. Sean Murray dialed back multiplayer expectations in more recent interviews, but didn't come out and say that running into other players was cut. There are still videos on Steam's page for No Man's Sky that at least exaggerate the scale of the game.
I imagine what happened is that they were against a wall. They lost a ton of work in a flood that took out their offices, and that alone may have led to some things getting cut. Even after announcing a release date, they had to push it back some, and in order to prevent another major delay things had to be scaled back in some places. Multiplayer (such as it was) was a great candidate for that because it would require a lot of work to implement something that would barely be seen. Portal functionality may or may not have been replaced with black holes. Some features may have just been time sinks that they could scale back and implement later, after the launch. They had a flood over a year ago that set them back, Sony was probably putting pressure on them to get the game out (Murray has said there are things about that agreement that he wasn't allowed to talk about) so they took a calculated approach to what they could dial back. The game was also originally going to be a PC exclusive, but the deal with Sony involved a PS4 version, so some cuts may have been necessary for that as well (though console limitations are becoming less of an issue). I imagine at least some of these things will be added later on.
And as I said in the last Roundtable, I think Sean Murray was as much of a fanboy in interviews as players can be. I think he was super excited about some things that weren't finalized and may have spoken about things when he shouldn't have.
I used the phrases "I imagine" and "I think" a few times in the two paragraphs above, because I can't know for sure. However, if we got some info about this stuff pre-release, I wouldn't have to imagine.
Ultimately, I like what we have (more on that in the full review). It's missing some things that people were expecting, but I don't think we were lied to at all. Plans had to change for whatever reason, and that happens in game development, but when the game is as much of a media darling as No Man's Sky (even a Stephen Colbert interview), they could have mitigated the backlash by managing expectations better.
EDIT: The full review: http://cheerfulghost.com/Travis/posts/3100/no-man-s-sky-review-procedurally-generated-everything