Use your skill points in strictly dexterity and strength, until they are 100. Get all Katana skills. Now you should be able to kill any thing in one hit (That third Katana skill is a one hit kill). To completely finish the game, get the aura for healing Far East men, take out the Far East capital (Its easiest if you take your armor off, seeing as their one hit kill can no longer hit you). And then buy an army of Shogun Ghosts (100k apiece). Now you will be able to walk into battles, turn on the aura, and watch as your ninjas wipe everything out, while getting healed.
(And all you get after all of this is a "You Win")
Right. This game was fun, and easy. On Normal, just get the Far East guy. Train on rouge quests until you have about 500k. Trust me, if you hit the "No, Maybe Something Else" button a couple times you can get much higher amounts. (The amount is based off of your level, so after each battle the amount you will be able to get will go up). With those levels and money, buy some good equipment from the large cities of the Far East.
Overachiever
Dude! You just completed the Overachiever achievement in Hanna in a Choppa and won the Overachiever badge and 30 points!
Level 20 is easy... very easy
8 is hard to perfect though.