Trigun is the story of Vash the Stampede, also known as the Humanoid Typhoon, who has a $$60,000,000,000 (sixty billion double dollar) bounty on his head due to the amount of chaos and destruction he leaves in his wake, most of which isn't really his fault. The curious thing is, however, no one dies. That's factually true, although rumors can get out of hand. He's still essentially the most badass man on the planet. His favorite food is donuts.
The thing about Vash is he's supposed to be the most badass man on the planet, but he's actually a big spazzy dorkwad (so no one really believes that he's Vash—there's a running gag where townspeople believe bigger, badder, meaner characters are Vash instead). I have issues with badass characters who are big spazzy dorkwads (e.g. Misato) because in anime, they're portrayed so fucking dichotomously. A character will have a badass moment and then in the very next second revert to being ridiculous. And Misato eventually proved herself to be more badass than dorky, but Vash did not. He does have a bunch of awesome moments and his gunmanship is impeccable, but his character still seemed heavily lopsided in favor of the spazzy Vash. So I don't think I ever fully warmed up to him, although I liked him well enough.
How do you add supporting characters to a show about a man who travels from town to town causing mayhem? Why, you make them insurance agents, of course! It's probably one of the most amusing and clever ideas I've seen. Meryl Strife and Milly Thompson are sent to find Vash and try to keep him out of trouble because the company is really tired of paying out insurance settlements because of the destruction he causes! Ha. Meryl and Milly were my favorite characters. Notably, they're not anime babes in the slightest: the most feminine part of Meryl's design is that she wears earrings, and Milly could easily be mistaken for a dude. Milly is also hella tall, and her high-pitched voice seems incongruent with her appearance but is perfect for her character. She's very naive and provides a lot of the comic relief, whereas Meryl is more of the straight man, so to speak. ALSO: they're both packing heat. Meryl's got dozens of two-shot derringer pistols, and Milly's concealing a ginormous minigun that shoots X-shaped projectiles than can pin people against a wall and stun them. The two of them become very attached to Vash, and it's neat to watch them grow over the course of the series.
The other major supporting character is Nicholas D. Wolfwood, a badass priest who serves as a foil to Vash. He's also an excellent gunman, and he's strong enough to lug around a giant cross wherever he goes. He's sort of like a more spry Shepherd Book. Except not.
The series starts out very light-hearted and episodic, and it's not till close to halfway through the series (with the menacingly titled "Diablo") that it starts to get really serious. And when it does get serious, it gets superduperangsty. It does retain its light-hearted core, even though a lot of it is that anime-style humor with exaggerated animation and voice acting that I am not a fan of.
Like all anime heroes, Vash has a MYSTERIOUS PAST that includes A WOMAN and THE MAJOR VILLAIN OF THE SERIES. Like I said, it's like Cowboy Bebop! Except I liked Spike way more than Vash. As you learn more about Vash's past, you see that there's more to him than his dorky exterior (you can also tell this from his episode previews, where he waxes philosophical). Vash has one defining characteristic, however, that emerges as the central theme of the series: he does not kill. Ironic for a man so good with a gun, no? But he values life above all else, and he always seeks to preserve all living things. Even the bad guys. The show takes a look at how this philosophy works in practice: it's not flawless. There can be situations where, in an effort to preserve one life, you end up causing the loss of other life. Morality is complex!
Honestly, I started to find Vash's extreme pacifism tiresome and irritating. Now, I don't like killing people as much as the next guy, but he experiences Supreme Angst (with lots of crying) over, like, everyone and everything. Even when a villain is killed. He was a bad guy! He was trying to kill people! People are alive because he is dead! The situations seemed pretty clear-cut, but Vash was always trying to make sure no one died, period. It's an interesting concept to explore, really, because it's not really touched on in most shows and movies where there's a lot of collateral damage and death that goes uncommented on. And I understood his philosophy, but it became really repetitive to revisit it episode after episode with little variation. Not that it didn't lead to some great scenes now and then.
I found some of the sci-fi concepts intriguing at first, but in the end, they seemed to be mostly unexplained. There didn't seem to be any reason for some of the more gigantic characters or the special powers exhibited by the gang of villains that come after Vash (I will note that the villains were pretty damn cool, unexplained though they were). And most of the fundamental world-building aspects didn't really make a lot of sense. But, oh well, that stuff isn't really the point of the series; it's just the backdrop for a big meditation on the morality of killing.
Overall, I thought Trigun was good but not great. I never really got into it as much as I wanted to; I know it's beloved by many. My thoughts and feelings are almost completely in line with this review, which is much better than this post. As I said earlier, I was reminded of Cowboy Bebop, which I also liked but did not love, but I liked Cowboy Bebop more. Obviously, however, Trigun has a wide appeal, so if you're a big space Western fan, this could still be right up your alley.