Abzû is an adventure video game developed by Giant Squid Studios and published by 505 Games.
From the official Site: ABZÛ is an epic descent into the depths of the sea, where players will explore beautifully rendered ocean environments with fluid swimming controls. The experience draws inspiration from the deep innate narrative that we all carry within our subconscious: the story of ABZÛ is a universal myth that resonates across cultures. The name references a concept from the oldest mythologies; it is the combination of the two ancient words AB, meaning ocean, and ZÛ, meaning to know. ABZÛ is the ocean of wisdom.