for all of you clash of the titans buffs, the original myth of persus had a sea monster named Cetus as the actual princess devourer.
Persus happened upon andromeda when he was returning from slaying medusa, a task he was given in order to obtain the freedom of his mother from a cruel king. Poseidon was said to have sent the Cetus to kill andromeda because her mother casseopia claimed her beauty was above that of the gods.
Dispite my enjoyment of the movie, that was artistic lisence. The Kraken was also a scandanavian/norse belief, the greeks had actually very little to do with the open ocean beyond the agean sea, they belived that the realm of the dead was reachable beyond the rock of gibralter (aka the pillars of heracles to them). On strictly movie terms, I wish the Kraken had more screen time lol.