People who are giving this game bad reviews just because it's different are fools. The game is a spin-off, I personally think that it's a nice change from all of the stealth. Snake is about stealth, Raiden is cutting up fools. Great game, definitely worth your time.
If you are browsing and the thought, "Oh look, another MGS game!" excitedly crosses your mind...disregard that excitement. The first 30-40 minutes of play were a blast. You get to play as Raiden which was tempting enough for me as an MGS fan, but then after you have gone into "blade mode" for the 200th time in one area to slice your enemies into a billion tiny pieces, it starts to get incredibly repetitive.
This is not a bad game by any means, but having just returned God of War Acension, the last thing I needed was another hack and slash with less interesting in-fight mini games, worse upgrade potential for weapons, and a story that was so focused on action that just about every line of dialogue made me cringe.