Finished it today. Must have rushed it like hell because I finished it in only 30 hours. The story in the last few chapters were great, and some of the revelations were mind blowing. Terrible direction, though, to structure the story so that you spend 90% of the game with nothing happening then cram everything in the last 6 hours.
Anyway, about a 6/10 game or so. I think Kojima's gameplay is really outdated. This is basically MgsV all over again but instead of being a soldier doing stealthy infiltration, you are a deliveryman doing delivery orders. Everything has to be solved with a delivery, you must go through ton of menus preparing your tools before going into a mission, just like MgsV mission structure, and both have a dead open world and terrible direct combat when you think of going this route. It's time for Kojima to reduce the usage of menus in his games a little bit, and abandon this limited mission structure for a more fluid and natural gameplay, than the "oh he's sick, deliver antibiotics, it doesn't work, return and deliver the entire doctor to him". It's way too video gamey and very outdated imo.
I get the idea Kojima was aiming for. The guy built a very big dead and empty world with the concept of players building it themselves to make traversing the world less tedious for each other. On paper this is a great concept that uses the online feature in a creative way. However, it should have been used in a smaller world and with a gameplay loop that's actually fun. Ultimately you meet zero unique events on your way in each delivery. BTs become a nuisance more than fun and fighting those cargo thieves is terrible because of the shit combat. It's just a tedious gameplay loop.
Anyway I kinda feel a relief since I bought this a long time ago and really wanted to delete it to free space for other games.