IMA, the endgame of Ninja Gaiden X is not only the easiest part of the game, it's also the most forgetable.

I can remember most of the early levels pretty well. The towns in the first and second, the airship in the third, the larger city in the 4th and 5th, the catacombs in the 6th, etc.

But after stage 10, it all is a blur. I remember Doku. I rember a lever puzzle that was more annoying than satisfying due to all the acrobatics involved. I won't say much more as not to spoil anything, but I just remember the theme of an area (e.g., fire, ice) and some bosses.