Seeing Zeus getting pissed off and his first command, "LET LOOSE... THE KRAKEN!"
The destruction of Argos, a good mix of old-school effects and real stuff of people washed with water. It indicates that much of the destruction was caused by massive waves before the Kraken even reached the city.
Zeus goes the extra mile, even though King Acrisius death is assured thanks to the Kraken's rampage. The king of the god's takes Acrisius' statue (which is basically a physical representation of the man himself) and slowly crushes it. Causing the king of Argos to die a slow and painful death.
The giant scorpion fight. Sadly, the last of the warriors accompanying Perseus, including poor Thallo die in the ensuing skirmish. But they did fight very well, given the circumstances.
Also, Perseus managing to kill Calibos.
The fight with Medusa, where she's a terrifying figure who can't be looked at directly, and who can strike you well before you know where she is, where exactly those hisses are coming from. note Compared to the original myth, where she was asleep when killed. And the Visual Effects of Awesome; those are consistent flickering fire effects on a stop-motion animated figure!
After being shown as a mostly calm lady, Thetis cuts loose when Cassiopeia says Andromeda is more beautiful than the goddess in her own temple. After causing a quake that shatters the head of the massive statue of Thetis loose, the goddess brings the head to life to speak right to the horrified crowd.
Thetis: Hear me, o vain and foolish mortal woman! You dare compare your daughter's beauty to mine and in my own sacred sanctuary!
Thetis snaps that if Andromeda isn't sacrificed to the Kraken in thirty days, the Kraken will destroy all of Joppa. For an encore, she sets off another quake that shakes the place apart and sends the crowd scattering. Thetis may be a kind goddess but this shows her temper can rival Zeus'.
When Bubo rescues Pegasus from Calibos's followers.
Later, when it appears Perseus and Pegasus wont make it in time to save Andromeda. Bubo appears in an attempt to distract the Kraken long enough for help to arrive. Let me repeat, Bubo, the little mechanical owl often (rather harshly) accused of being The Scrappy faces down a creature more than five hundred times his size.
He also flew right up to Calibos's giant vulture and scared it away, which took a lot of nerve considering it wasn't something Bubo could've escaped from if he lost.
When Andromeda insists on going with Perseus to find the Stygian Witches, she shows she's an Iron Lady instead of a Damsel in Distress.
Perseus: I'll set out in search of the Stygian Witches on my own. Andromeda:No. We will ride with you as far as their shrine. It is a long and perilous journey. Perseus: Too perilous for a princess. Andromeda: You are not my lord and husband — not yet. In the absence of the Queen, it is I who'll command.
Pegasus rising up out of the water after the battle with the Kraken; you can tell he was preening for all those who were watching.
Near the end, when Perseus seems to be down and out and when it comes time for the Kraken to be unleashed, Zeus sighs in defeat and tells Poseidon to release the Kraken... while sneakily putting up a figurine of Perseus to have him get a Heroic Second Wind.
How does Perseus solve the riddle and earn Andromeda's hand in marriage? He cuts off Calibos' hand (which has the item needed to solve it) and throws it down onto the steps, right in front of the goddess favoring Calibos and all the people that worship her.
Andromeda gets a quiet one. When Calibos summons her to his lair, he gives her a jeweled necklace, then tries to play on her sympathies. Of course, that doesn't last long, and he shows his true colors as a sadistic monster. Finally, he tells her to leave... and Andromeda calmly rips off the necklace and throws it to the ground. A very understated "screw you" and a strong hint that Andromeda has some steel in her.
After his son Perseus loses his magic helmet of invisibility, Zeus tries to compel his daughter Athena, goddess of war and wisdom, to gift Perseus her pet owl, Bubo. Athena is having none of it. The sheer balls it takes to tell Zeus, all-powerful King of Gods and Men and the Known Universe (not to mention your own father) to "go jump in the lake" is utterly inconceivable. And sensational.
The shot of Perseus coming out of Medusa's lair, lifting her cut-off head in one hand, is epic and brings home the incredibility of what he has done.
