Gordon Freeman, male protagonist, HEV suit, crowbar, futuristic, Combine soldiers, City 17, dystopian, headcrab, alien creatures, resistance fighters, Alyx Vance, sidekick, physics-based puzzles, gravity gun, action pose, intense combat, dark corridors, eerie lighting, abandoned buildings, high-tech laboratories, Vortigaunts, allies, Xen, otherworldly dimension, atmospheric, decaying urban environment, wide-angle shot, dynamic shadows, high-resolution textures, advanced particle effects, immersive, first-person perspective, Valve, science fiction.