Best free Linux "first-person 3D" games

VISUAL - In gaming, first-person 3D describes a style where you see the world entirely through the eyes of the character you control, with everything around you rendered in three dimensions. This means you perceive depth, distance, and space realistically, and movement feels like actually walking, running, or looking around in a real environment. Typically, you might see the character’s hands, weapons, or tools, but the focus is on experiencing the game world directly rather than watching the character from an external viewpoint. It’s a perspective that emphasizes immersion and makes exploration, combat, and interaction feel immediate and personal.