This one was definitely dark as fuck. I mean... the HE getting his face torn off + animal torture was a bit over the top for a "Superhero" movie that didn't give any indication it was that "grown up". As opposed to going into something like The Punisher or Deadpool, for example. But at the same time, I grew up reading comics and they got dark as fuck, and pretty sexualized, too. So I'm not really sure where to draw that line.
Overall, I did like the movie, though. I dig the dark background because it really sums out why Rocket is such a "hard" character-- gruff, very dark sense of humor, etc. He's seen some shit and found a way to live through it. Adam Warlock was the only real letdown for me. In the comics he's a fucking badass. Here, they went with "You pulled him out of his cocoon too early!" to explain snipping his balls off. Meh.