- "No Man's Sky," an ambitious sci-fi adventure game, allows players the freedom to take on the galaxy as they wish
- Vast open-universe game has so many planets, it would take 584 billion years to visit every one
- "No Man's Sky" puts few restrictions on how to accomplish game's aims
(CNN)Sean Murray's brow furrows in concentration. He's trying to remember just how many planets players can explore in his latest game.