post-apocalyptic setting, underground metro, dimly lit tunnels, abandoned stations, gas mask, military-grade armor, makeshift weapons, eerie shadows, mutant creatures, survival horror atmosphere, stealth action, decaying structures, rusted trains, flickering lights, scattered debris, atmospheric particles, damp surfaces, reflective puddles, intense firefights, claustrophobic spaces, 3/4 view, high contrast lighting, detailed textures, immersive environment, dystopian Moscow, narrative-driven DLC, expanded storyline, character-driven plot, enhanced graphics, additional content, atmospheric soundtrack, tension-filled gameplay, first-person perspective.