post-apocalyptic setting, underground metro, Moscow, dimly lit tunnels, rusted trains, gas mask, military grade ammunition, survival horror, first-person shooter, enhanced graphics, improved textures, dynamic lighting, atmospheric effects, character model upgrades, Redux version, original version comparison, detailed environments, mutant creatures, stealth gameplay, narrative-driven, immersive world, 3/4 view, over-the-shoulder camera, ambient occlusion, high-resolution textures, real-time physics, soft shadows, particle effects, improved AI, remastered audio.