There are few actual twists the script tends to be fairly straightforward with intentions and motivations and many of the game’s arcs and themes tend to just exist in their own bubble without interacting with one another in a cohesive manner. Narratively, Metal Gear Solid V is the simplest game in the franchise, perhaps to a fault. Recognizing and analyzing Ground Zeroes isn’t so much important to understanding The Phantom Pain ’s story as it is important to understanding how The Phantom Pain ’s story is told. There are issues with this expectation, however most notably, The Phantom Pain ’s apparent lack of interest with everything that occurred in Ground Zeroes. The Phantom Pain ’s narrative absolutely expected its audience to have played through Ground Zeroes.
While it isn’t handled with nearly as much grace as it should have been, arcs, themes, and characters are all introduced in the prologue that aren’t necessarily reiterated in main game. GZ is undeniably an important piece in understanding TPP ’s puzzle. The same can, and should, be said for Ground Zeroes ’ relationship with The Phantom Pain.
Simply analyzing the latter ignored all the crucial context found in the former. It’s certainly possible, but the Tanker chapter directly sets up the events, arcs, and themes of the Plant chapter. Discussing Metal Gear Solid V without discussing Ground Zeroes is akin to discussing Metal Gear Solid 2: Sons of Liberty without touching upon the Tanker chapter.