underwater landscape, Subnautica game, alien ocean world, vast seabed, coral reefs, kelp forests, deep-sea trenches, volcanic areas, bioluminescent underwater rivers, diverse aquatic species, submerged caves, research outposts, sunken alien facilities, survival theme, exploration, resource gathering, base building, day-night cycle, dynamic lighting, wide-angle shot, panoramic view, 3D environment, realistic textures, immersive experience.