What makes this story exceptional is how universal its subject matters are. Everybody goes through growing pains, but in the case of the Elric brothers Edward and Alphonse, their transition into adulthood is nothing short of hardcore. The boys lost their mother, who they literally tried resurrecting, but in addition to failing miserably with the alchemical ritual, Edward lost two limbs and Alphonse his entire body. Turns out, despite the sheer magical potential of alchemy, it can't be used to bring people back to life.
There's a good reason why Fullmetal Alchemist has few peers. A story like this is impossible to create unless you've survived fucked up shit, possess the social support and intelligence to make sense of it and have the skills as a storyteller to convey those experiences. The author clearly thinks ill of shortcuts to personal growth (miracle cures, religion, etc.), evidenced by the first episode alone.
It seems obvious to point out the inspiration to this series is human darkness - even ethnic genocide makes it into the plot. It's astonishing how deep Fullmetal Alchemist goes with its harrowing concepts, yet rarely feels depressing. The characters talk about their emotions, then keep pushing forward, make new allies and grow as people. To be fair though, they don't actually get many chances to lament their misery, because the intense plot constantly whips them forward.
The main mysteries involving the plot are discovered shortly into the series, but the bad guys quickly clean house and cover everything up. This killing creates an incredible tension that sets the pace for the entire rest of the series. Not only that, but on many occasions the episode's cliffhanger is just brutal, reminiscent of Attack on Titan. Friendly advice: DON'T watch this series before bed, make the time to binge it!
The cast of characters is varied in genders, ages and body types. Their designs are focused and simplistic, though not without depth. Unlike how females are often drawn in anime, in Fullmetal Alchemist they look nice, but not overtly sexualized. There's also just about no fanservice. Even some of the evil characters are surprisingly humane, which indicates the author's ability for deep empathy. That's a real feat, considering the eyes she has for true darkness.
