As good as the gameplay was, the fundamentals of controlling Snake and interacting with the world and NPCs, I don't feel like the game design held up its end of the bargain. It desperately needed some variety in level and mission design. While there are a handful of genuinely excellent missions, they're far outnumbered by the cookie cutter "Snake, we need you to sneak into an open compound and Fulton/destroy a target because something something Cipher" ones.
It feels like such a waste that you never get to put Snake's new controls to the test against a some proper MGS bossfights. Sahelanthropus was decent, but Quiet and Volgin were so disappointing compared to what the series has had to offer in the past. The Skull Unit fights were just chores.
And, yeah, the story's a load of rubbish. I'd love to see what it was meant to be in the original design doc before Kojima dragged his heels for years and Konami called a premature end to it, but as it stands the game is unfinished and completely unsatisfying. I honestly can't think of a game with worse pacing. It starts off strong in the first couple of missions, then nothing of consequence happens from like mission 3 to mission 27, then everything is shoved into the final three or four missions of Chapter 1. And Chapter 2 is just a drawn out montage of Liquid making sly faces in the background of innocuous scenes before it all ends, apropos of nothing, with a stupid twist explaining an obscure plot point nobody ever thought about twice.
Just dumb decisions in storytelling, too. Why are there two viral outbreaks on Mother Base? Why doesn't Mission 43 happen during the first outbreak, while Skull Face is still a threat, so it can actually create some stakes and some ill will toward the game's main villain? Instead it's just thrown in out of nowhere in Chapter 2, when the main threat of the game is over and done with. And I don't know when Kojima decided that the radio play was the greatest form of storytelling, but if I ever hear another Cassette Tape it'll be too soon. At first I thought the shorter cutscenes meant Kojima had learnt to be more succinct, but instead he just put all that MGS4-style waffling in audio-only form.
Ugh, what a thing. I can't help but both love and hate it. I put 80 hours into it last year, and I still fully intend to go back and S-Rank all the missions to get the Platinum, but at the same time it's so disappointing in so many ways. Those trailers were a masterclass in misrepresenting a product.