If you were upset that you could only use one weapon in Ninja Gaiden 3, then perhaps you may want to pick up the latest DLC that was released for the game today, entirely free. Amongst a slew of other paid-DLC releases, a Ninja Pack 1 Lite DLC was released that costs absolutely nothing and adds the Eclipse Scythe as a weapon in story mode. Also added in this package is a free multiplayer stage.
The free DLC will be automatically downloaded for the PlayStation 3 version of the game and the Xbox 360 version of the DLC can be downloaded here. You can see what the scythe will look like in action, as well as some paid-DLC, in the trailer below.