This is not a game. It's a convoluted Japanese storytelling circle-jerk. Clichés are heaped upon cliché.
Make no mistake. This is not a game that will keep you entertained for gameplay's sake alone. You need to be extremely interested in the story telling and cinematic elements of this game to even bother. If you've played MGS games before, maybe it'll interest you more. Personally, I haven't and could not really care less about the storyline of the game if it's a chore to advance the plot.
The gameplay consists of sneaking around warzone cities and tunnels trying to get to objectives. It's supposedly a game of stealth, but in reality it goes about as far as Assassin's Creed did in that department. I guess a lot of people really think it's fun and cool to pretend to be some badass lone wolf skillfully and quietly eliminating targets. Unfortunately you really have to use your imagination with this game, because you can 'hide' in plain sight mere feet away from the enemy and they'll never notice you. It's also clear that they are all deaf, because you can leap off buildings 10 feet behind them and they're none the wiser.
The best part of the whole thing is that, just like Assassin's Creed, if you are discovered it's generally not too hard to dispatch dozens of enemies all by yourself.
My personal favorite, however, is how easy it is to shake off pursuers if they do discover you and you decide you don't want to fight. All you have to do is turn a corner, walk up to a wall and press triangle and all of the sudden the enemies can't see you. They'll walk around looking for you (even though you're kneeling right in front of them) and a few moments later they'll give up and walk back to their original location.
Stealth game indeed....
Anyways, aside from that you have a clunky and unresponsive interface, long repetitive missions and a main character that's completely uninteresting. Maybe some people really get excited by the cheesy clones Japanese gaming companies keep throwing at us as main characters, but if I've seen it before I've seen it a million times. I really have.