'Ninja' is voiced by Billy West. West is a prolific voice actor that is known for his work on television shows such as Futurama, Doug and Ren and Stimpy.
The cinematics in I-Ninja were directed by Don Bluth. Bluth has directed video games such as Dragon's Lair and is probably more famous for his animated films such as An American Tale, The Secret of NIMH, The Land Before Time, All Dogs Go To Heaven and many others.
A sequel was planned and was actually in development, however due to the liquidation of Argonaut Games, the sequel was eventually cancelled and never saw the light of day.