*Galaxy Express 999 (the first movie, though I liked the few eps I saw of the TV series too).
Watch the TV series! The movie gets so, so many things completely backwards. The only good things about it are the animation and the decoration over the fireplace.
For starters (spoilers marked):
Movie: "Tetsuro" is a 15-year-old slacker who failed to grow up.
Series: Tetsuro is nine years old and had to grow up too early.
M: "Tetsuro" gives the robot police a happy go lucky Benny Hill style chase around the train station.
S: Tetsuro is hunted for sport having done nothing wrong.
M: "Tetsuro" steals the ticket, immediately loses it, gets a replacement from "Maetel" but could just as easily steal another one.
S: Stealing is bad. You gotta earn the ticket, and if you lost it, you should earn another one. Maetel's offer is precious.
M: "Maetel" is missing for like half of the movie and is a reward for the hero.
S: Maetel is always present, Tetsuro doesn't need to to earn her presence.
M: "Maetel" is a clone of "Tetsuro"'s mother or something, weird convoluted stereotypically anime shit.
S: Maetel is something else entirely, I won't even write that down in a spoiler, go watch the series.
M: "Maetel" is a cowardly asshole who betrays "Tetsuro".
S: Maetel has two motivations, one plaintext, one metaphorical, both of which are
sinister and ruthless but not cowardly.
M: "Tetsuro" wants to destroy the mechanized planet but doesn't bother learning the first thing about it, like its name. How were they drafting battle plans?
S: Tetsuro trusts Maetel and doesn't have much choice in it, there's no way to find out other than go and have a look.
M: "Tetsuro" needs a mechanical body to take revenge on Count Mecha, and turns into an anti-robot extremist once he's done.
S: Tetsuro needs a mechanical body to live forever to fulfill his parents' wish.
M: "Tetsuro" spends an hour brooding about muh revenge against Count Mecha and another hour planning a robot genocide.
S: The series is 40 hours long. It takes Tetsuro
5 min 29 seconds to get revenge. He goes on to do more interesting things in the remaining time.
M: Robots are evil and must be genocided.
S: Most robots were to an extent tricked into mechanization (literally tricked/forced/extorted or metaphorically seduced by Robot Satan) and don't deserve a genocide.
M: Riuz is in love with a child-murdering sadist, we're meant to sympathize nevertheless.
S: Leruiz is in love with a heroic image she's built around a small-time scammer and bully. We're meant to ponder how desperate but weak and lazy people would pin their hopes on just about anyone.
M: Antares the pirate lives on Titan, which is a libertarian paradise and no place to raise kids.
S: Antares lives in an asteroid and suffers from loneliness.
M: "Tetsuro"'s mother's necklace is Captain Harlock's symbol. It looks like something a husband would leave his wife to remember him by. (And why did the family fall on hard times, why weren't they rescued by Harlock?)
S: Tetsuro's mother's necklace is a lady's necklace and his only physical memento of her. It's not a mcfaggin and it doesn't have to be.
M: "Tetsuro" is driven by revenge.
S: Tetsuro is free to have a change of heart any time, most episodes' plots present arguments why he should or should not.
M: "Maetel" is completely absent for the castle scene.
S: There are two castles (one a chapter adaptation, one original), and Maetel is involved in both and is awesome.
M: The Cosmo Gun is the only thing which can kill robots. But there are only four of those in the universe. That means everyone except the four people with the guns should give up on trying to fight globohomo!
S: Robots die a lot (thus proving a mechanical body is not the end-all). Tetsuro even gets into a gun duel against a robot
before he gets a gun and wins through his humanity.
M: A shitton of established, prominent, fan-favorite characters make a fanservice appearance and hang around. "Maetel" is absent for half the story and is just one of the many characters. E.g. you're meant to know going in who Captain Harlock is and should be more excited about him than the new fluffy-hat lady.
S: Tetsuro meets a variety of new civilian characters, a few at a time, most of whom die and others he has to part with. Maetel is with him all the time, she is uniquely precious to Tetsuro, his friend and the only constant.
M: "Tetsuro", despite being a hissy-fit-throwing asshole, somehow assembles a Fanservice Team of Friends which show up for the final battle (but don't actually do anything useful except waste firepower).
S: Tetsuro is alone and he doesn't go to war, he goes to get his promised mechanical body. He did meet some fanservice characters but left them, they only can help him by the lessons they imparted.
M: The movie did not need to happen, the war could be won by "Maetel" alone any time if she ever decided to stop being a cowardly asshole.
S: The TV series has a keystone artifact (bad) but also a cool scene with the train (good). The book lacks the train scene (bad) but has the best resolution of all, mythical and with a callback to one of the very first chapters/episodes. Either way the series is about Tetsuro's search for happiness and is not obviated by mcfaggins.
And the songs in the series are better.
You don't need and should not binge it. Watch an episode at a time in order, preferably before bed.
There are 113 episodes, 3 tv specials (longer versions of existing episodes with more backstory of the characters involved -- you can skip the 20-minute versions and watch the specials), and one summary. All of them are on nyaa and Discotek blu-rays.