Game Modes
Subnautica currently features four different Game Modes.
Freedom
Disables the need for food and water, but you will still need to keep an eye on your Oxygen. Energy is consumed by all electric tools, including the Cyclops, Seabases, and the Escape Pod in this game mode.
Hardcore
In addition to the food and water requirements of Survival mode, Hardcore mode adds permadeath. There are no second chances. In Survival and Hardcore mode, a food and an H2O bar are added to the HUD. In Hardcore mode, there are no low Oxygen warnings.
Creative
In Creative mode player death is disabled as well as damage to the player's Vehicles. Materials and Blueprints are not required for crafting. There are no energy requirements. The story is disabled. This mode is currently experimental only.