Leviathan

Leviathan is a sci-fantasy harem AVN, taking inspiration from the likes of Cyberpunk, Eternum, and Pacific Rim.
Dive into a world where giant monsters roam the oceans, technology is embedded beneath your skin, and danger lurks around every wave. As Jack, a sailor just trying to make his way, you'll build your crew, explore mysteries beneath the sea, and maybe even find romance—or several. Your choices shape your personality, affect your relationships, and decide whether you'll save the world or chase your own desires.

[From Itch.io]