Great animation, cool sci-fi world, great music, pretty graphics and sound, decent combat and fun travel. Its about exploring and hiking, such unique gameplay thats entirely gear based. Its a new type of challenge in gaming.
Its ton of fun to plan out going from one spot to another (or several) and decide what equipment is the best to use, how to carry and balance it all, what issues could arise, the risks, rewards, time, etc.
Its one of the only open world games that actually needed to be for the gameplay loop to work. Lots of fun stuff to build out and see along the way. Its an emotional and cool journey. Story was classic Kojima, good and bad.