Let's get the obvious stuff out of the way: Clash of the Titans is an incoherent, slapdash, tedious mess. It in no way improves on the 1981 original, and in particular the substitution of by-the-numbers CGI for stop-motion Ray Harryhausen creatures makes it feel like a millwork knockoff.
Not that the original was any kind of treasure, but with beefcake Harry Hamlin, bony Burgess Meredith, and a robot owl for comic relief, it was goofy entertainment. The new one seems determined to give us the brooding, gritty side of the tale, as if the problem with the first was a lack of angst. As Perseus, the half-human son of Zeus, Sam Worthington has two modes: angry and blank. (He was more fun, and more expressive, as a 9-foot blue guy in Avatar.) It's true that the original myth has a built-in Freudian conflict—Perseus kills his mother's father—but whatever a movie with giant scorpions and a snake-headed woman might need, it's not familial Weltschmerz.
The writing and conception are lazy, even for a remake. Besides recycling the only memorable bit of dialogue from the original film ("Release the Kraken!"), the new Titans borrows liberally and haphazardly from Star Wars, Lord of the Rings, and even Fellini (the decadent Argos aristocrats are glammed up like extras from Satyricon). As the chief villain, Hades, Ralph Fiennes arrives in clouds of black smoke seemingly straight from the latest Harry Potter shoot, scarcely bothering to change out of his Voldemort costume on the way. And as Zeus, attired in armor that looks to be constructed entirely of lens flare, Liam Neeson barely manages a pout when the script clearly calls for vengeful wrath. (I'm guessing the script actually says that in capital letters: VENGEFUL WRATH.)
Even the Kraken, the only really impressive beast in the movie's menagerie, turns out to have a disconcertingly familiar face: Its reptilian head and rows of teeth make it look a lot like a squiddish descendant of H.R. Giger's Alien. In that sense it's at least true in spirit to Harryhausen, whose Kraken basically retrofitted the Creature From the Black Lagoon with extra appendages.
Anyway, to the extent there's any interest to be had here, it is in the movie's half-baked ideas about the relations between Man and his Creator. The film's plot is set in motion by a human rebellion against the cruelties and caprices of Zeus and his cohort on Mt. Olympus. Voiceover narration at the beginning tells us that Zeus created man to love and worship the gods, and whenever humans fall a little short on the love-and-worship scale, the gods get testy and inflict assorted miseries until the prayer count goes up. But humans, being independent-minded, don't like this arrangement and start doing various anti-god things, like toppling a big Zeus statue. Which of course just makes Zeus even more irritable and susceptible to his brother Hades' Cheneyesque suggestions that what these humans really need is a good dose of death and destruction.
But if the gods seem like a bunch of posturing, insecure blowhards, the movie isn't really much easier on the humans. The rulers of Argos are just as vain as their Olympian counterparts, and their war against the gods doesn't seem born of anything much more than ego and grandiosity. That leaves Perseus in the middle, disgusted with the whole lot.
I briefly hoped the movie was going to take a Yojimbo turn and let Perseus lay waste to all sides. But after raising at least the outlines of some intriguing moral questions, Clash of the Titans settles for just making Hades the bad guy and leaving it at that. Perseus and Zeus even have an awkward father-son reconciliation at the end, where Zeus confides that while he really wanted humans to love him, he didn't want the battle to cost him a son. (Which, when you think about it, is an interesting moral to take away from the biggest box-office hit of Easter weekend.)
The original Clash of the Titans was part of a wave of films, including Superman (1978), Flash Gordon (1980), and Raiders of the Lost Ark (1981), that updated the spirit of old Hollywood serials for the age of blockbuster effects. Their absurd stories and winking asides were part of the fun. The new Clash of the Titans suggests that while the blockbuster effects are still with us, the fun is a lot harder to come by.