Hark! Spoilers ahead!
Avengers: Infinity War killed it - literally. The source material it's based on however, is far removed from what you see on the big screen.
It's important to know that the movie is actually (loosely) based on the comic Infinity Gauntlet, as opposed to Infinity War, which was its sequel.
It's also important to note that Thanos' motivation behind the attack is very different in the comics.
He's enamoured by Lady Death, the physical manifestation of death in the universe. She's the one who asks him to restore the balance of the overpopulated universe.
To this end, he gathers the Infinity Stones... and yes, he brutally rips through Vision in both the film...
... and the comics.
In an effort to impress Lady Death, Thanos snaps his fingers and removes half the population of the universe (just like in the movie). Cosmic beings like Galactus and Eon then come together to figure out how to deal with this sudden cosmic threat.
Meanwhile, the Silver Surfer gathers The Avengers as well as Earth's other heroes (Wolverine, She-Hulk, et al) to put a stop to Thanos. They go in, and promptly get their asses handed to them.
Here are some of the biggest differences -
1. The X-Men join The Avengers in the battle against Thanos. Wolverine's bones promptly get turned to rubber.
2. Cyclops suffocates inside a box that forms around his head.
3. Iron-Man almost got his armour beaten off in the movie.
In the comics, it's implied that he has his entire head ripped off.
4. In the film, Thor gets a new weapon and goes into uber-lightning god mode.
In the comics though, Thor is turned into glass and shattered.
5. In the movie, Spider-Man gets a few good hits in, before disintegrating along with half of the universe.
In the comics, he's beaten to death by Thanos' newly created lover, Terraxia.
6. Captain America holds his own against Thanos in the movie.
Things are a whole lot less dramatic in the comics. Captain America has his neck broken by a single slap.
7. In the film, Thanos tortures Nebula by pulling apart her various mechanical components.
In the comics, Nebula is kept alive in a burnt and extremely painful physical state.
8. Nebula wrests the gauntlet from a distracted Thanos, healing herself and banishing Thanos into deep space.
However, Dr. Strange and Adam Warlock rescue him. They convince him to help them defeat Nebula.
9. Nebula is tricked into reverting everything back to normal, after which she is defeated.
In the movie, she's slowly turning to the good side.
10. In the end, Thanos goes off to live as a farmer on a distant planet (similar to the ending of the movie), while the Infinity Gauntlet is broken down.
The stones are scattered through the universe, and they can never be used together again.
So there it is. As you can see, the movie and the comic aren't exactly all that alike, but it's still great that Marvel decided to tip its hat to some iconic moments from the comics.