Hunter x Hunter had two anime adaptations, one that came out in 2011 and one that came out in 1999. The 2011 version is a far more faithful adaptation of the manga, but that doesn't mean it's exactly the same. When you look at the Hunter x Hunter manga versus the anime, you'll find a number of important differences.
One of the biggest changes involves Kite, Ging's friend and Gon's mentor. In the manga, Kite appears in the first chapter, but in the anime, he first appears during episode 75. Also, if you thought Hisoka was unsettling in the anime, wait until you see him in the manga.
Kite Is Introduced Differently
Maha Zoldyck Doesn't Appear In The 2011 AnimePhoto: Viz Media
Leorio Is Stronger In The Manga
Censorship In The AnimePhoto: Viz Media
The Gate Situation Played Out Differently
Gyro's Role Is Less Clear In The Anime