Contains Some Significant Changes, But Overall a Respectful Retelling

Rating: 9/10 (4 April 2010)

I watched the original Harryhausen film when I was quite young, and it remains one of my favorite movies. As a result, I had mixed feelings before the remake's release: anticipation mixed with worry about what might go wrong. As luck would have it, my fears were mostly unfounded.
Now you must understand that at their hearts, both the old and the new Clash of the Titans films are visual showpieces; the story of the film, while not insignificant, is mainly there to facilitate the action scenes, and there's nothing wrong with that. Both films also play fast and loose with Greek mythology, adding in new creatures, for instance (the Kraken has never had anything to do with Greek mythology). So long as you understand and accept this, the films are very enjoyable rides.
Sam Worthington takes the role of Perseus, son of Zeus and a mortal queen, rescued from the sea after his mother's husband, King Acrisius, tried to drown him (some people just can't handle their wife bearing a demigod). When Perseus is a young man, he suffers the loss of his adopted family during a fight between some soldiers from the city-state of Argos and the god Hades. Picked up by the surviving Argosians, he ends up in the city-state proper, where Hades shows up to deliver an ultimatum: as punishment for Argos's rebellion against the gods, the princess Andromeda must be sacrificed, or the ancient, terrible Kraken will be unleashed to destroy the city. Perseus wants vengeance on Hades for what happened to his family, and as such joins the mission to save Argos, hoping that it will bring him closer to his own goal.
Your mileage may vary on Worthington, but I thought he did well, at least as well as Harry Hamlin in the original. Liam Neeson steps into Laurence Olivier's shoes as Zeus, and while he doesn't quite get across the divine wisdom Olivier did, Neeson does an impressive job of portraying both the majesty and the power of the king of the gods. While he seeks to punish mankind for their rebellion, he has a soft spot for his son, and subtly aids Perseus on his quest, perhaps even hoping that he won't have to destroy Argos. Jason Flemyng plays Acrisius, Perseus's mortal father, cursed by Zeus for trying to kill his son and transformed into the monstrous Calibos. The character is bitter and resentful of what has happened to him, but Flemyng manages to make him a little sympathetic as well, though still clearly a bad guy. Credit should also go to the actors playing the Argosian soldiers who accompany Perseus on his quest; though I sadly can't name these performers, they do well at bringing some lightness and humor to the journey.
The action scenes, the movie's main draw, are very, very fun. Director Louis Leterrier takes full advantage of the capabilities of CGI, staging elaborately choreographed battles with the film's monsters, including the giant scorpions, Medusa and the Kraken itself. I doubt you can top Harryhausen, but I think the remake does right by the original. I saw this in 2D, so I'm not sure what difference 3D would make. That said, if you can't see it in 3D, don't worry about it, as I felt the movie worked just fine even when "flat".
Now the film isn't perfect, and feels a bit too grim and serious during the first act. Luckily, by the time the quest to see the Stygian Witches begins, Leterrier finds his footing and gets comfortable with the story he's telling us, and the movie becomes WAY more fun.
There are changes made to the story, including Hades being the villain instead of Thetis (a bit sad to see him get stuck as the bad guy once again, but at least he makes an impressive villain here). Also, Perseus is not paired up with Andromeda as per the myth (and the original film), and instead ends up with another mythological character, Io. It's a major change, but it's understandable given that Perseus and Andromeda have all of one scene together in the remake, so pairing them up would feel rather odd within the context of the movie.
Overall, while Clash of the Titans has some flaws, it nonetheless remains what the original was: an impressive visual spectacle, with the story acting as a framework for the creatures, exotic landscapes and battles. If you know this going in, it should make for a fun day at the movies.