This is very short anime with good animation, decent music and voice actors.
Story starts slow with characters finishing single mission per episode till about halfway of the season. Then story goes a bit deeper. There is no big push for explaining character's motivation or to present their stories so it's bit hard to get attached to main crew. Story is dark and violent. History of opium and how it corrupted people was a strongest part of the plot. Revenger is not pretending to be a deep series. What i like the most about story is that author is not trying to explain everything to the viewer, instead taking "show not tell" approuch.
I like how entire anime is being done completely in one season. Story is being told fully.
There's a lot of lgbt themes being represented in this show, normally that would be a good reason not to watch anime as usually it feels super forced and unnatural. This time hovever certain characters or male prostitution just makes sense for the story.
If you enjoyed animes like: Akame Go kill or Requiem for the Phantom you will also enjoy this one. This is not a masterpiece just a solid, enjoyable show that doesn't pretend to be another Paranoia Agent or Monster.