If you've played the other Ninja Gaiden's, stay away from this one and don't believe the hype, even from other users.
Story: Non-existent for the most part and very lame. Apparently Ryu gets hit with a curse where his dragon sword is obliterated and sucked into his arm and that acts like a virus which poisons him the longer he lets it linger (wow, really)? The character dialogue's and exchanges are less than memorable and you'll sit for the most part thinking: "What does this have to do with anything and why can't I get into the story"?
Gameplay: Has been improved, but only slightly. Just as the review said, just because the game is more difficult doesn't make it better. Here's NG3 in a nutshell: Run down a hallway/corridor, fight enemies in a square room. Run down a hallway/corridor, fight enemies in a square room. This kind of crap I expected back during PS2 days with games like Chaos Legion (very similiar level design which has me wondering). However there are times where you'll press a button and nothing happens or you feel a horrible delay in between. The combat doesn't feel as fluid as other Ninja Gaiden releases and man is that dull. Combo's are on-screen for the Wii U Gamepad making it easy to see what move to do and make a bloody mess of people, but do you really want to pay $60 for that and extra weapons? The new characters and weapons add a bit of fresh air but it's not enough to cover the other noticable faults of the game (feels like an arena killer where you're put in a box and you just kill people... all game long).
Sound: Terrible. Voice acting is just one of the worst (changed this to Japanese with English subs and made the dialogue a bit more bearable to listen to )and the most annoying parts is when Ryu grabs his arm and starts making those stupid noises while he walks to the end of a level. They couldn't think of anything better and this IS NOT Team Ninja quality.
Graphics: Are pretty decent and for the most part show off what the Wii U can do. Obviously you'll see better titles down the road, but this was still visualing pleasing. It's just too bad you run in a straight line for the entire game so you can't really admire it as much as you want to. There are also tons of framrate drops which is unacceptable for a fast paced-hack and slash.
All in all this game is worth a rental but that's about as far it goes. I wasted my money buying this thinking that there would be some MAJOR improvements (an improvement to level design to not make them so linear would have been nice as well as some puzzles) but instead, they add DLC in the terms of characters and weapons and at the end of the day, you just feel like you're forcing yourself to the end of the game to complete it. If you're a true Ninja Gaiden fan and loved the original NES and first 2 for Xbox/PS3, DO NOT buy this game. If you're a casual gamer or someone who just wants blood everywhere and you don't care for depth of story or anything else, then buy this game.