sandbox game, interactive physics, multiplayer, creative building, character customization, face posing, ragdoll manipulation, prop placement, game mods, community content, Steam Workshop, user-generated levels, puzzle-solving, in-game scripting, Lua programming, dynamic lighting, 3D environments, open-world exploration, first-person perspective, construct mode, play mode, diverse textures, realistic materials, virtual reality support, custom game modes, online servers, collaborative gameplay, dynamic shadows, ambient occlusion, detailed character models, physics-based gameplay, interactive scenarios, modifiable terrain, user control mechanics, flexible game rules.