The use of authentic pirate gibberish like "Davy Jones' locker", "aarrr!" and "bonnie lass" were all appreciated, plus the obligatory pirate movie cliches of plank walking, thieving monkeys, talking parrots and, of course, bad teeth. Keira Knightley channels Kate Winslet well. The supporting cast is solid, especially the bumbling oafs on both the evil pirate crew and in the British navy.
But towering over all assets was the transcendantly weird, over-the-top, magnificent lead performance of Johnny Depp as Capt. Jack Sparrow. Wow. Everything about the performance is brilliant -- the showy mannerisms; the deadpan comic timing and delivery; the dreadlocks and eyeliner; and, most notably, Depp's conscious channelling of Keith Richards throughout the whole thing. Not only is Depp acting more flamboyantly than anyone around him, but the other characters all respond to his weirdness in kind.
(To explain: it's not like Grease, say, in which Stockard Channing's portrayal of Rizzo happens to be a three-dimensional performance in a one-dimensional movie, without any of the other characters acknowledging. Instead, everyone around Sparrow reacts to him like he's Prince or something, and not just another pirate.)
There's a rhythm and a goofiness to Depp's performance that's just remarkable to behold, and he doesn't break character once. The performance has total integrity to it, and god bless Gore Verbinski and Jerry Bruckheimer for letting him run with it.
Why isn't Depp a bigger star? See Pamie's recent Fame Audit of him, which notes:
Johnny Depp has found a way to keep his films and his acting choices almost completely removed from how the public views him as a person. He doesn't play the distraught, quick-tempered, skinny-minny-loving, chain-smoking, mumbling weirdo in his films. He is at his finest when playing a tortured, beautiful freak. And we love him most in the dark, when we're alone, staring at his gigantic, captivating face on a movie screen. So much so that we tend to turn our heads in public, excusing his behavior or simply ignoring it, waiting for him to get back up there where we want him
It's interesting that Nicolas Cage got Depp his first part, because it's Nicolas Cage's career that Johnny Depp's should most resemble: small cult films that earn him respect that lead to small cult comedies that garner more respect which lead to Oscar-winning drunk portrayals followed by a series of crappy big-budget films that give him enough money to take bigger risks that lead to Adaptation. Johnny's got a similar sense of humor. He's a freak for love, just like Nic. He knows the power of a good cigarette. What's keeping Johnny from reaching this level of fame. Is it self-sabotage?
See the movie.