People often think of Greek heroes as quite intelligent folk because of Odysseus;* this is, I feel, a mistake. On average I would say that most of them would probably be outwitted by small puddle of water. (This is true of Oedipus for all his riddle solving: right, so you know you're destined to kill your mum, but you marry a woman of about the right age whose husband has recently died without asking questions? You, sir, are as dumb as a pile of rocks. And Oedipus is at the upper end for heroic intelligence; most of them just relied on stabbing things a lot and hoping that worked.) This may be Clash of the Titans one faithfulness to Greek myth: Perseus is quite wonderfully thick about so many things and is clearly determined that his stupidity will get many people killed.* Clearly he takes after his dad, Zeus, who is also not v. bright and probably forgets about ruling the universe on a regular basis when distracted by his shiny armour.
*Sometimes I feel O's reputation for high intelligence is unwarranted. He does make some terrifically stupid decisions in the Odyssey.
*Most people in Greek myth died horribly because of stupid actions of heroes, so that's about right.
In conclusion: RELEASE THE KRACKEN AND EASE YOUR STORM.
ETA: Also, people who get upset that Clash of the Titans messes with Greek mythology, clearly have no idea how much the Greeks messed with that themselves. Just reading Apollodorus' Library of Greek Mythology makes you realize that they could simultaneously have 5 different variants of the same myth. This is the culture that had a sequel to the Odyssey where Odysseus is killed by his son by Circe, who then promptly married Penelope and brings her + Telemachus back to Circe's island where she then married Telemachus and made them all immortal. That had people who believed Zeus was dead and were willing to show you his tomb. Compared to the Greek imagination, the one that came up with RELEASING THE KRACKEN is a pathetic and feeble thing.