Fun Fact: Ninja Gaiden was another game that was novelized as part of Nintendo's Worlds of Power series.
Ninja Gaiden was the beginning of a series that would run into the current console generation. Players took the role of Ryu Hayabusa, a ninja on a quest to avenge the murder of his father. Ryu eventually discovers a conspiracy by an ancient evil to destroy the world, and has the chance to get his revenge and save us all in the process.
Ninja Gaiden was heavily influenced by Castlevania. Ryu's main weapon was a katana blade, but he also had secondary weapons like shuriken (throwing stars) and fireballs that drew off his “spiritual strength.” Lamps on the walls could be destroyed to reveal spiritual strength items and other power-ups. Ryu could also hang on walls, and each level ended with a boss fight.
Ninja Gaiden's cinematic cutscenes were extremely stylish and attractive to players as the technique was very unique compared to other games, but the reputation of Ninja Gaiden was founded on its difficulty. The game was straight-up brutal. Stage 6-2 in particular was maddeningly difficult for most players to pass.