One Piece Green: Secret Pieces revealed that an early concept of Crocodile would have challenged people with difficult riddles (possibly in homage to the mythological Sphinx, per Arabasta's many parallels to ancient Egypt). Accordingly, his hook-hand would have been shaped more directly after a question mark.
In the manga, Crocodile's skin color is a more natural light skin color, as opposed to the anime's gray skin. In the manga, the poison hook beneath his golden one is far thinner than in the anime.
Impel Down Arc
In the anime it is partially seen how Crocodile changes outfits, as his shoes are laced by the Emporio Ivankov's Dancers. In the manga, Minozebra is defeated by Crocodile's Sables, while in the anime he is defeated by Jinbe's Gosenmaigawara Seiken. In the manga, Minorhinoceros is defeated by Jinbe's Gosenmaigawara Seiken, while in the anime he is defeated by Crocodile's Sables.
In the anime Crocodile mentioned that they were falling down out of the sky because of Ivankov. He is in fact blaming the okama, but this was proven wrong in the next episode, where it showed detailed explanation on what happened on their way to the war. The conversation between Akainu and the Whitebeard Commanders and Crocodile was extended in the anime.
In the manga, when the world learns of Doflamingo's sudden resignation from the Seven Warlords, Crocodile is not specifically shown or even confirmed to appear, only a shadowy figure with a long non-fur coat over his shoulders with a cigar in his mouth. In the anime, the cigar is removed but the coat was changed to Crocodile's trademark fur coat and Crocodile's golden hook is shown, confirming his identity in the anime.
The manga image.
The anime equivalent
The added shot of the hook.
Translation and Dub Issues
In the 4Kids dub, Crocodile underwent several edits. After his first fight with Luffy, Crocodile dangled Luffy upside down with his hook instead of impaling him with it. Strangely, in the next episode of the dub, Luffy was right-side up with Crocodile's hook being around his neck, but was still hanging upside-down in some shots. Another edit Crocodile suffered was that instead of being weakened by Luffy's blood in the final fight, he was weakened by his sweat. In spite of this, it was roughly edited- there were a few frames where the blood can still be seen. Also, in the hidden tomb with Nico Robin, he merely hit her in the back. In the original version, he impaled her through the back.
Additionally, scenes with Crocodile smoking cigars were cut. However, in one episode, 4Kids forgot to edit his cigar at one point. His personality was also changed to be much more sarcastic in the 4Kids dub, such as calling Luffy "desert doodoo". Also, due to cutting out the Little Garden arc, his feeding Mr. 3 to his Bananawani was for pointless reasons, which itself was a plot hole as he said he ordered Mr. 3 to follow the Straw Hats since they left Loguetown when he didn't even know about them yet.
In a mock-trailer in episode 50 of the anime series Gintama, a Crocodile lookalike of Kondou Isao (the stalker) is seen charging towards Shimura Tae. He is knocked away by a "Gomu Gomu Pistol" move pulled off by Tae as she yelled, "Gomu Gomu".
In Episode 117 of the anime (roughly at timing 19:55), he is shown lighting his cigar with two intact hands; this shot notably excludes not only his hook, but also his many rings.
When Igaram first mentioned Crocodile's former bounty, he said it was 80,000,000. However, when Crocodile was introduced in person, his infobox said his bounty was 81,000,000.
Miss Goldenweek's Rainbow Color Trap reveals that his dream was to become the Pirate King.
His animal theme is the crocodile. His name, the Bananawani he kept as pets, and his large scar (which resembles a "crocodile's smile") are all reflections of this theme.
The soundtrack playing during Crocodile's defeat is Dvorak's New World Symphony, specifically the 4th movement, "Allegro con fuoco". It was the third time in the anime when a piece of classical music was played in the anime (The first being Buggy and Gaimon's farewell, during which Chopin's Etude in E Major played, the second being Dr. Hiriluk's last speech, during which Ave Maria was played and the fourth being when the zombies claimed Absalom as their leader, with Ludwig van Beethoven's rendition of (Ode to Joy).
Crocodile is the first Warlord to be defeated by Luffy.
Crocodile is the only one of the original Seven Warlords to possess a Logia Devil Fruit.
In the 2nd, 3rd, 4th, 5th and 6th Japanese fan polls of most popular characters, Crocodile was ranked the 15th, 25th, 28th, 15th, 18, respectively.
Though no direct inspirations have (thus far) been confirmed by Eiichiro Oda, Crocodile's appearance and methodology strongly evoke two iconic villains of Western pop-culture:
Peter Pan's Captain Hook, the archetypal hook-handed pirate, who is also strongly associated with crocodiles (though in hostility rather than fondness); moreover, the the 1953 Disney adaptation also centers his climactic scheme on a time-bomb.
In SBS Volume 56, a fan asked Oda why Crocodile was wearing his own clothes since he was still in prisoner clothes after he's released, Oda replied that he went to Newkama Land and got his clothes from there. This is depicted in the anime.
Crocodile's birthday, September 5, comes from the Japanese transcription of his name's first and third syllables since 9-5 can be derived from cu-co.