At some point, John Woo's production company option'ed or maybe even bought the movie rights for Metroid. That would have been a weird one.
As far as doing a single protagonist movie, I feel like many horror and adventure movies, without even touching the more arty things, have huge chunks in them with only a single character. Things like The Decent or REC come to mind. The Revenant also... most of The Martian... Even not going that far into the arty territory, you have things like All Is Lost by Chandor with Redford alone on a sinking sailboat. If you feel things get too dry, you can always insert some flashbacks here and there, or have the character taking audio logs. A movie could also expand on the Metroid universe with the space pirates and the bounty hunters and places that are not ancient ruins and abandoned mining facilities. Personally, I would enjoy if somehow Metroid ended in the hands of some borderline experimental filmaker (I mean, we have Gerwig and Baumbach doing a Barbie movie, so anything is possible!) and we got an almost totally silent exploration movie all about atmosphere. Like a Terrence Malik or one of these Thai director like Pen-ek Ratanaruang or Apichatpong Weerasethakul (both made very atmospheric films set in the jungle).