"Graphical downgrade" refers to a situation where the visual quality of a video game or graphics-intensive software is reduced, resulting in less detailed or realistic graphics compared to a previous version or initial presentation. Full definition
In response to the arguments of those claiming it is a fake, they argue that almost all AAA games, including GTA 5, took noticeable graphical downgrades compared to trailers — not to mention that the reveal trailer only contained traces of in - engine footage, mostly being cinematic. (rdr2.com)
It was at E3 2014, after Ubisoft showed off more gameplay footage, that talk of graphical downgrades begun to trend. (techtimes.com)
Besides the disappointing graphical downgrade, players are getting an identical experience to the console version. (metacritic.com)