No Man's Sky creator Sean Murray has shown off an extended look at what players will actually do in his ambitious "open universe" space game.

The footage, posted by IGN, shows Murray exploring a random planet, scanning for discoveries, alien creatures and shooting crystals for resources.

Items you acquire can be kept in your ship and then sold for Units, the game's currency, which can be exchanged for better ships that travel further and store more resources in their hold.

You will also have to buy upgrades for your player character - such as a jetpack for easier navigation, or improved space suits to visit toxic or radioactive planets.

Weapons will also be upgradable. And, like ships and everything else in the game, weapons will also be procedurally-generated.

Cause trouble on a planet - Murray shoots a goat at one point, for example - and you will cause Sentinels to appear. These are a race of self-replicating robots who will attack you with increasing ferociousness if you fight back.

A five-star wanted system, identical to that found in Grand Theft Auto, determines the reaction of the Sentinel forces. Raise your wanted level to the max and tanks will quickly appear to take you down.

"Luckily they haven't patented that particular mechanic," Murray quips.

Death causes players to lose anything they have not sold or stored already. Otherwise, you respawn on the planet you were on and where you left off.

Murray ended the demo by taking his character into space and demonstrating how players can scavenge for resources by scooping up cargo dropped by ships that had been taken out by other forces.

Finally, Murray headed off to the centre of the galaxy - No Man Sky's mysterious eventual end-game goal. What's at the centre, he was asked? "Peter Molyneux," he jokingly replied.