Well, they're pretty good. That's the first three, anyway. I don't know why anyone would like the mess that is MGS4, to be honest. Kojima pulled that shit out of his ass and it shows. It ruined the series for me; it's just so, so bad. The characters are all ruined, the gameplay is made even worse (and it wasn't that great in the first place), the conclusions make no sense because Kojima felt the need to wrap up every single storyline even though he couldn't possibly do it in a satisfying way. Nanomachines turn into some sort of superpower bullshit that's used to explain everything even though they were never set up to be THAT important in the previous games.
Pretty much every single plot twist came out of nowhere (the one with Ocelot, just sayin'). Good writers use foreshadowing/subtle hints/whatever for their plot twists, Kojima. Remember that.