Plot

Ninja Gaiden 3 will yet again feature Ryu Hayabusa as the main character. Although his black leather outfit from the previous two installments will make another appearance, Ryu has been seen with a new metallic black suit in recent screenshots. It has a few visible differences as well. His toes are now covered with metal, presumably used for his new Kunai Climb.
In the Gamespot video, it is revealed that Ryu gets a request from the Japanese Self-Defense Force, the Ministry of External Affairs. He is sent to London where he fights unidentified terrorists. Afterwards, he faces a mysterious hooded opponent who kills the Prime Minister. After the fight, the mysterious opponent tells Ryu to "open [his] eyes" and the Dragon Sword is absorbed into his right arm. Ryu escapes the missile firing and is picked up by Defense Forces. In the end cutscene, the mysterious hooded opponent appears on the news forecasting that every country in the world must agree to his surrender in 7 days, or will result in immediate destruction.

Gameplay

The game will feature a few new mechanics and changes. The new Kunai Climb involves Ryu climbing onto certain walls with the use of his kunai, which he can use to attack enemies from above. In other situations the player will have to be stealthy, as Ryu can now sneak up on an enemy and kill him with a single strike. Enemies speak while fighting, saying phrases like "Get around him!" and "Send backup!". Enemies do not die quickly, and they will suffer and scream in pain when injured. They are no longer decapitated or dismembered, instead they will just bleed and weaken.
Some changes include the slide maneuver, which replaces the Reverse Wind Technique from the previous games. Ryu will use it to get through small passages as well as to attack enemies. The Ultimate Technique concept has slightly changed in the form of Ryu's cursed right arm known as the Grip of the Murder. When he kills a specific number of enemies his arm will glow red. Then, the player can charge up for an ultimate attack that is fueled by absorbing nearby fallen bodies instead of essence. Unlike past games, the HUD will appear only when Ryu is engaged in battle, then fade out later. The Muramasa store is no longer present; Ryu's weapons will be upgraded over time, and items are now only found in chests and in certain enemy corpses. The Dragon Statues that allowed Ryu to save and heal will be replaced by a scripted Falcon who swoops down to Ryu's hand and saves at specific points in the level.
The ninpo concept has been revamped. Instead of slots, it is featured by a green bar where Ryu will have to kill enemies to fill it. Once it's full, Ryu can now cast a ninpo and after the animation, his health will be restored. One new ninpo has Ryu transforming into a fire dragon. Both the PlayStation 3 and Wii U version of Ninja Gaiden 3 will have optional control schemes. The Wii U version may be played touchscreen controls similar to that of Dragon Sword. This is to take advantage of its unique controller. The PlayStation 3 version will have Move compatibility. This is to give players "a new visceral edge when battling and slicing through their enemy's flesh and bone."