Red Orbs All Around!!!
This is a very easy thing to do, altough it can take a while.
In Athens, when you are about to win Meduza's Gaze, u'l notice that when Aphodite tells you to freeze the minotaurs you have temporary infinite magic (with or without the Dairy Bastard costume). There is a way to take this into you're advantage: instead of using meduza's gaze use poseidon's rage to kill the minotaurs. The first few kills will render some red orbs (dunno how many) but after a while u'll notice that they'll stop giving you these after they die. DON'T STOP KILLING THEM AT THIS POINT! Just keep on using the same thing and level up poseidon's rage until it's max. After it is position urself at the center of the room and keep using it (never forgetting to press the CIRCLE button). You will receive 1490 red orbs for each "lap" (1000 hits) it takes time, but you will b able to max the blades, poseidon's rage and medusa's gaze, and if you want to, you can even save up some orbs for later.