Perhaps I phrased that poorly, but I meant actually showing what the game is about and combat and the such rather than just exploration of the scope.

There is nothing that tells you what to do or where to go in this game. It's completely open. You can loot ships that you destroy to obtain money. You can trade goods, and use the market, you can explore and discover. All of these things provide you with a means to upgrading your warp drive. The more your warp drive is upgraded, the farther you can go. The ultimate "goal" of this game is to get to the center of the galaxy. It's not a concrete goal, but it gives you something to work towards if you so desire. 

Actually there's plenty of footage...GameInformer had so much info shown this year. A Big Q&A, even a 30min gameplay session with techincal stuff covered...

The structure is simple but deep depending on how you want to play. You have all the ingredients you need:

Goal: To get to the centre of the universe where you will find 'an answer'.
Motivation: You have to upgrade your ship to reach the centre of the universe, upgrade your weopons to survive and upgrade your suit too,
Consequence: In order to do the above you have to mine planets. Mine too much and your wanted level increases. Attacking space crafts or creatures also puts your wanted level up

That's the basic structure to keep you playing. You can specialise in a number of different ways:

Adventurer: Chart planets, animals or plants and simply enjoy the freedom of infinite space
Trader: Buy and sell the resources you mine.
Pirate: Atack space fleets and steal resources to sell to the highest bidder.
Faction: Protect a certain faction and eventually you will become one of them.
Escort: Escort freight ships through space, protecting them from pirates.
Miner: Dig deep into the planets surface to uncover hidden cave systems and caverns

All of the above are just some examples of what you could be if you wanted. There are other things that Sean Murray just doesn't want to give away. We know that there is a lore inolved and that some planets have ruins and portals to other 'places'. I suppose you could spend your time trying to uncover that lore, in which case you could add 'Archiologist' to that list. There is a periodic table that enables you to combine resources and create something new, but this isn't going to be explained. It's up to US, the gamer, to work out what each one does and by discussing it online we will eventually create our own 'hand book'.

IGN guy - "So, what awaits us in the center of the galaxy? Spiritual enlightenment, untold wealth, immortality?"

Sean (NMS creator) - "Peter Molyneux?"

Oh boy, I laughed so hard. I love how Sean is aware that people are still wondering what the hell the game is about, and is not afraid to make a joke on that account.

Peter Molyneux was my first thought too when I heard about the center of the galaxy bit.

Thanks for all your answers ;). It seems an interesting concept, I'm already intrigued by what's in that centre XDD. That, and the lore will keep me busy. If the world is rich enough, I will give it a chance, it seems like it could be a groundbreaking game, I hope so!

Should be abundantly clear by now that Sean Murray isn't going to divulge more than he wants to.  If you're that curious, you can always wait until after it launches and then watch Let's Play and Twitch live streams.

The Elder Scrolls Arena and Daggerfall had a similar procedurally generated world for the most part. Of course that wasn't on the same scale as No mans sky but Bethesda have increasingly went for a more handcrafted approach through the years. I'm sure they still use a form of the tech for dungeons, unless Skyrim was 100 percent handcrafted as well in which case they have completed moved away from it.

What would be great is i they used No Man's Sky tech to alter the landscape around a narrative driven RPG. Imagine playing something the size of The Witcher and then on beginning the game again, you have a completely different landscape. That would be the definition of replayability.