I gotta parrot some of the other responses here, MGS would make a better mini series than a film. To me, a film works best when it has tight constraints and a concise vision, you’re getting a snippet of the picture, not the whole picture. Several hour long epic movies have never really done it for me, IDK if it’s my ADHD or what but a big all long ‘epic’ puts my ass to sleep (looking at you LOTR).
That said, I feel like for a story as weird and nuanced as Metal Gear’s, a limited TV series would work best. They could break each game down into an 8 part mini-series, and all together have say 3 or 4 seasons. They could even go in game order; MGS, MGS2, then do the prequel with MGS3, then the resolution with MGS4.
I think this would present way better, because let’s be real, you spend more time in the codec being fed exposition than a movie is even long. I’m not sure how they could accurately even capture it all without it feeling rushed.
I am worried we will have another Ghost in the Shell (Live Action) on our hands. It had the right actors, the right director, the right music, the right production design, even Masamune Shirow gave it his blessing. It all looked so good on paper, but upon release, man did they squander that opportunity. They completely missed the nuance, instituted their own (boring) story, and showed set pieces from the anime.
Like GITS, Metal Gear needs room to breathe, it gives you room to think too. There are lots of quiet moments for reflection and piecing the story together yourself throughout both pieces of media, and I don’t think studios or directors today have the ability to bring that through on screen, unfortunately.