Fenixp: . [url=http://media.moddb.com/cache/images/mods/1/26/25441/thumb_620x2000/thief2_2014-07-06_02-06-24-71.jpg]Of course they do. Light and shadow, reflections, blur effects - all of these are used pretty much since they were conceived by designers to subconsciously give their players hints, guide them and make the experience more interesting. Visuals are the primary way of communication between game and the player, of course they're also one of the most essential aspects a game can have.
Far from one of the most essential, otherwise we wouldn't have games in which the graphics are pixelated and without any of these fancy effects even in pixels, right? Plus when was the last time a game ever gave hints through graphics?
Don't let me say Minecraft. Oh wait, I already did that. The graphics are, to sum it up nicely, fitting for a SNES game if it could render that much an environment, and not the fest of light, shadows, reflections, motion blur, bloom, ambient occlusion, anti-aliasing, post FX, post processing and all of these fancy buzzwords. Yet the game is much deeper and more fun than say, a game focused solely on presenting graphics.
I haven't seen much games make use of the reflections. In fact, as far as I'm aware, first person mode in GTA V doesn't render a car's side mirror's reflections. The last time I played a game where reflections is how I advanced is Magrunner: Dark Pulse.
Fenixp: Ever heard of
Enviromental storytelling? I hear it's pretty popular with dem gamez.
Not sure, but whatever the case is, I have yet to see a game in which the graphics are needed.
What's more important is the art style. The graphics is only a tool to express the art style, and never the end goal.