YouTuber frost Danger took it upon themselves to put footage of Metal Gear Solid V: The Phantom Pain from E3 2013, 2014 and 2015 side-by-side for comparison. Luckily, frost Danger didn't take it upon themselves to speak over the video and instead did a straight comparison with stills of game footage and cinematics.
There is a difference between the years as development on the game progressed. As the released date for the game approaches it is being optimized for consoles instead of the unit it was built on and it is getting different lighting, textures, shaders and model quality.
No this video is not evidence of a downgrade.
There are things to note, the 2013 footage is very early on in the game, a lot of the time the lighting depends on the time of day in the game, and with the blur and colorful lighting it looks like the overall approach to the game's aesthetics changed at some point in development. Also, the cutscenes in Metal Gear are known to be both awesome and long, so we really can't judge too far into the comparison as we haven't seen gameplay.
