Ninja Gaiden (Xbox)

Phew! This game was hard. It is similar to the also great God of War, albeit much harder. I recommend this game to everyone who has access to an Xbox, it is an instant classic. A few tips:
Use Shuriken for bats.
Use The Art of the Fire Wheels for ghost fish, and if you are low on mana, use Vigoorian Flail.
If you like using counterattacks against smaller enemies, use the Dabilahro - a single counterattack is enough to decapitate most of them.
Flying Swallow attack is effective against most bosses.
Use The Art of the Inferno against the big angel-demon-thing (second to last level) - you are invincible when using it, and it takes about 1/6th of her HP for each attack.
The skull demon boss: use bow when it is wandering around, use Vigoorian Flail when skulls are attacking and dodge the main head when it attacks.