At the Eurogamer Expo 2012, Hideo Kojima revealed some new details, Ground Zeroes will feature base building elements and Smartphone Support.
• Use the helicopter to get back to base at any time.
• While flying back, you may get shot down.
• You will fly in real-time (not fast forward).
• Stealth is an optional gameplay aspect.
• Visual compromises were made for the open-world aspect.
• The day/night cycle is 24 hours long.
• A standard mission setup takes you through the story/world.
• The hub system brings you to smaller open worlds.
• You are able to customize the look of your base.