|Whenever you finish a mission, you are graded upon how much time it took you to finish the level, how many style points you received, and how many red orbs you collected, with S being the highest rank you can get. Human mode is a pain to S rank, because the enemies die too quickly to get any good combos off on them. Your main focus should be on time and orbs. Best tip I can say in general about S ranking missions is learn the the game. Level layout, enemy positions, and red orb locations, don't stress yourself out over it, you'll learn with time. For details on level requirements for S ranks, Click here.|
Also, see "King of the Palace".