I'm talking about the shinyness it's everywhere,his metal arms,the walls,the floors,the clothes,even their foreheads.It looks as if everything(including the character's skin) has some sort of enviroment map more or less o_O.Like almost everything has some shinyness or reflectiveness to it.The models are really low poly otherwise(you can see his shoulders are edgy),but the textures are ultra detailed.
If I understand you correctly, you're talking about specular mapping. This is another texture that simply says how reflective what bits are (and optionally colour information for the shine). That means you can make metal parts of a costume shiny without applying a separate texture/material/shader.
Yeah it's just specular lighting, using whatever approximations they've employed (probably a mixture of analytical specular calculated in the shader and cubemap environment probes, which is what most games use).