First off: The Metal Gear name was slapped on this title to help sales. I've tried to follow the story but it's so inchoherent and each cut scene drags on longer than needed.
As far as the actual game it is pretty fun. I had a blast setting up my base going in to abandoned bases to get supplies, recipies, and crystals needed to upgrade gear.
Than comes "The Dust", it is a harder version of the world your in where maps dont always work, enimies are harder, you have to keep track of oxygen, and its so dark its hard to make a sensible navigation plan. The Dust is both really cool and the weakest part of this game. Overall fun to play here and there but to aggravating to pop in and play through completion.