If the Merciless Ninjas don't Kill You, the Extreme difficulty surely will. despite this NGS is still a brilliant game..
NGS can be compared to classic old school games like shinobi and such, the difficulty is high and the frustration factor is too. However this just adds to the length of the game, the enemies within are nicely varied and the boss fights are epic. Once or twice you may feel like throwing your controller at your tv screen as you read the words "do you choose to give up the path of the ninja?" for the billionth time. However persevere and you will be rewarded.
There are a variety of weapons within NGS, dual swords, your powerful Dragon Blade, a pole which can be upgraded from wood into metal as well as nunchuks. Although this may not seem like a lot to some people. the amount of combinations and upgrades you can unlock for them really stops the game from ever feeling repetitive.
The Fighting in NGS is bloodthirsty, and some of the attacks make you wonder how you survived with the amount of blood that comes out of both you and the enemies. Your combos are deadly and brutal and so are the enemies. It's nice to see that the enemies aren't given a standard array of moves to fight with and in fact look like the attended the same ninja school as you. Flipping and jumping off walls and hitting you with stun batons, swords, grenade launchers, whatever they can get their hands on really. It's a little strange however to see an enemy come up and initiate and hold where they slit you're throat, and you to just then turn around after seeing a copius amount of blood spurt out, and continue fighting. The bosses are even worse, if you think the enemies are tough, wait to you fight you're first proper boss. Not only does he have a devestating amount of attacks, he has two pesky helpers that cannot be killed and respawn every time you attack them.
The graphics in Ninja Gaiden are good, technically proficient, but compared to today's standard on the next gen consoles, they don't fare too well against the likes of Metal Gear Solid 4 and Drakes Fortune. However all things considered this is still a port of a last generation console game thats been vamped up a bit so you have to take this with a pinch of salt.
The sound in Ninja Gaiden is great, the voice acting slightly cheesy, but this is an action game and you don't expect it to be as good as the voices may be in an RPG or in an adventure game. However the sound effects are top notch, swords clang and thump off different materials, and the sound of a sword tearing into an enemy is gruesomely satisfying.
In Ninja Gaiden its not all just action though, there are some slight occurences of platforming, and also ideas that are taken from an adventure game. You have to run across walls, water, up walls, basically most the enviroment to get to where you want to go. There is also some backtracking, and this backtracking comes with respawning baddies so you never get too bored of just wondering around. Also found in the game is the shop, here you can upgrade your weapons, buy potions, arrows, and new special moves (ninpo as they are known in the game)
The game also splits up the pace a bit by letting you use another character, called Rachel (who is a fiend hunter). Rachel is extremely strong but slow, where as Ryu is quick but weaker than Rachel, this means that you have to adjust your play style when you play as Rachel, which is a refreshing change from what can often just be Button Mashing as you play as Ryu.
There are only Three real complaints i have about Ninja Gaiden Sigma, the extreme difficulty, which is really unfriendly against first time players. the little replay value that Ninja Gaiden offers and the weird gimmick that Sony introduced where you have to shake the Sixaxis to complete a powerful Ninpo attack. This is just to showcase the fact the Sixaxis does have motion sensor capabilities, i wouldn't mind the fact it was tacked on, if it wasn't so awkward to use in the middle of a fight.