Abzû is an undersea exploration game. As a diver, the player can freely navigate around the 3D environment and rotate the camera. It’s possible to swim in any direction, flip through the surface, explore the bottom with an automatic headlight at night, etc. There is a three-tiered brief boost function next to the accelerator button for a quick boost. Beyond the interactive tutorial, there are no goal-related cues or HUD features. Air is inexhaustible for the diver.
Divers explore self-contained sections connected by tunnels. Swim through these to engage with different fish. Some ecosystems feed off others. The player cannot die and must solve tiny environmental challenges to advance. Sometimes swimming drones can be released. These open pathways and the diver can interact with them with a sound, but without further function. Finding hidden shells and freeing more fish are optional. Certain statues have meditation functions, encouraging players to relax and enjoy the environment. The player follows and watches the fishes while meditating instead of controlling the diver.
No background information is given at the start, but background pieces reveal the story of an oceanic culture and a progress system based on bringing orbs to temples. There are other sections that confine the diver to a 2D plane or limit camera actions to swim with enormous monsters, avoid mines, and glide in a jetstream with other fish. Sometimes you can hitch rides on bigger animals.