!!The 1981 film

* HeyItsThatGuy: Maggie Smith as Thetis, Burgess Meredith as Ammon, [[Film/DrNo the original]] BondGirl as Aphrodite (which doubled as a ParentalBonus when the movie was new), and, most of all, LaurenceOlivier as Zeus -- there's a reason ''Film/LastActionHero'' referred to him in this role.
* MoneyDearBoy: Part of the reason LaurenceOlivier was cast as Zeus. Probably the same with Maggie Smith.

!!The remake:

* CastingGag: The original featured Bond girl Ursula Andress playing Aphrodite. The remake also features a Bond girl, this time Gemma Arterton playing Io.
* CreatorBacklash: Louis Leterrier disowned the final film, claiming "it's not my movie" and refused to return for the sequel.
* DeletedRole: Apollo and Athena had major roles in the original cut, but the film was reworked. Apollo's role was heavily reduced, while Athena was almost cut completely. Additionally all the Gods originally had lines in the first scene on Olympus.
* HeyItsThatGuy:
** Solon, the Argos soldier with the most lines and screentime is played by veteran Irish character actor Liam Cunningham who has been in a billion Irish movies but is best known as [[Series/GameOfThrones Davos Seaworth.]]
*** Also, one of the other soldiers is The Hound.
** [[Film/HarryPotter Lord Voldemort]] is trying to get revenge on his brother [[Film/BatmanBegins Ra's al Ghul]].
*** Creator/LiamNeeson clearly loves playing those "grandiose deity" characters; he also famously [[HeyItsThatVoice voiced]] [[Film/ChroniclesOfNarnia a certain personification of God]] elsewhere. And for all of this, we love him.
** The only thing standing in his way? [[{{Film/Avatar}} Jake Sully]].
** Creator/LiamNeeson and Ralph Fiennes have fought [[Film/SchindlersList before.]]
** Draco was [[Film/CasinoRoyale2006 Le Chiffre]] and Io is [[Film/QuantumOfSolace Agent]] [[spoiler:[[UnfortunateNames Strawberry]]]] [[Film/QuantumOfSolace Fields]].
** Perseus' adoptive father was [[Film/{{Inception}} Maurice Fisher]] and [[Film/TheUsualSuspects Kobayashi]]. Who was in... so many movies he deserves his own trope for being the HeyItsThatGuy in so many movies.
*** His adoptive mother was the [[Series/DowntonAbbey American wife of a British lord]] and [[Film/OnceUponATimeInAmerica girlfriend of a Jewish American gangster]]. And she was Film/KickAss's mother.
** [[Film/XMenFirstClass Azazel]] plays Acrisius/Calibos. And [[Series/StarTrekDeepSpaceNine Dr Bashir]] plays Hermes.
** Film/JackTheGiantSlayer has a rather larger role as one of Perseus' team.
** Apollo has later become [[{{Film/Immortals}} Zeus]] in that other crappy Greek Mythology movie. Thankfully, his career was saved with a great performance as Bard the Bowman in ''TheHobbitTheDesolationOfSmaug''.
** Andromeda is [[Film/TheChroniclesOfRiddick Jack/Kyra]] in the 2010 film, and [[Film/DieAnotherDay Miranda Frost]] and [[Film/TheWorldsEnd Sam Chamberlain]] in the sequel.
* OldShame: Alexander Siddig who played Hermes, referred to this as "the lamest movie I ever made", claiming 50% of his performance was deleted.
* SoMyKidsCanWatch: Creator/LiamNeeson took on the role of Zeus because his sons thought it would be awesome.
* StarDerailingRole: For both Sam Worthington and post-production 3D conversions in general.
* WhatCouldHaveBeen:
** Matthew Belamy was writing the score, but had to abandon midway through as Music/{{Muse}} started a tour.
** As detailed [[http://www.chud.com/23299/by-zeus-the-version-of-clash-of-the-titans-you-didnt-see/ here]], the film's original story was drastically different:
*** Perseus and Io's relationship was purely platonic; with a romance developing between him and Andromeda during his time in Argos. It would have ended with a MaybeEverAfter situation between them.
*** Perseus's main motivation for going after the Gods in the original was to show that mankind did not need to rely on them for anything. Likewise he wished to save Andromeda because he felt that nobody should be sacrificed for the sake of the people. In the finished film, he just wants revenge on Hades.
*** Apollo and Athena had major roles, conspiring against Zeus and Hades. Apollo was originally the one who offered Perseus passage onto Olympus.
** Zeus was far more villainous in the original cut. The film would have ended with Perseus going to Olympus and putting Zeus and the rest of the Gods on notice. Zeus would offer him a seat, but Perseus would refuse - saying his father is a dead fisherman.
** The original idea for the movie was a CrossoverCosmology with [[Myth/MesopotamianMythology Tiamat]] waging war against the Greek pantheon and Perseus being assisted by [[Myth/EgyptianMythology Thoth, Osiris]], [[Myth/MesopotamianMythology Marduk]] and [[Literature/TheBible Yahweh]]. He would also apparently have a romantic affair with some "Cthonian Earth goddess." (The filmmakers apparently have something against Andromeda for some reason...)

!!Wrath of the Titans

* ActorAllusion: Not only does Hephasteus sound a bit like [[PiratesOfTheCaribbean Davy Jones]], but has the scraggly beard from human!Jones and even says "release the kraken" at one point (in reference to the first film).
** At the end, Zeus is basically using [[ThePhantomMenace the Force]] on the Makhai [[spoiler:and Force Lightning against Kronos!]]
* HeyItsThatGirl: Korrina, Andromeda's female soldier who comes to an unfortunate end, gets reincarnated a couple thousand years later into a girl named [[Film/{{Cinderella2015}} Ella]] and has a happily-ever-after ending.
* TheOtherDarrin: Creator/RosamundPike replaces Creator/AlexaDavalos as Andromeda.