
Several years ago, I sat-in on a "games as literature" course, and promptly got into an argument with the instructor. We were talking about Portal, and he argued the dark metal unportalable surfaces seem "sinister" because of their color, rustiness, sense of alien materiality and permanence, lack of affordance, etc. (This was also an introductory course, so a lot of his effort went towards getting students to make critical arguments about games at all.)
I argued that interpretation was irrelevant, and that type of thinking was obfuscating how these surfaces actually function to players: in Portal you don't think to yourself, "that wall is scary," but you more often think "I can't portal there, let's look somewhere else" or "wow that wall looks cool on these graphics settings." To me, the wall material told more of a paratextual story rather than a diegetic story.