Ninja Gaiden isnt a breeze but anyone who primarily discusses the difficulty of the game is overexaggerating. Like JKtrix said, once you've spent a good time practising with the game is becomes less of a bother. I found when I got to Chapter 5 the game became less difficult. But difficulty should never put you off a game, truely hardcore experiences are my fondest memories of gaming, not from the controller snapping side of it, but the satisfsction of kicking a games ass when its throwing everything at you. And just the intense rush throughout.
Ninja Gaiden was tremendous fun, I dont actually own the game, when I played and beat the game it was from borrowing a friends Xbox and copy of the game. Now I own a 360, I could buy it cheap. Or rather wait and buy Sigma for the PS3. Im split between the two. But Im not really in any position to buy either cause im broke.
Admittedly not the easiest battle but he is cake walk compared to Alma and her latter form.