More info on NG3
The online multiplayer mode in Ninja Gaiden 3: Razor’s Edge is known as “Shadows of the World”, which is broken into co-op and deathmatch. The deathmatch portion (“Clan Battle”) supports up to eight players and has the main objective of killing the other team, but also a sub-objective where every player must fulfil a task in the form of a “Shadow Contract”. There is a feature that ties in with this that may have you betraying your allies, so that should be interesting (or infuriating).
The co-op mode is known as “Ninja Trials”. This sounds like the Firefight feature in Halo where your goal is to survive while also performing specific tasks that will earn Karma. This will increase your ninja’s level and, “as you gain levels, you’re able to perform more actions.” It’s possible to play this mode by yourself.