Death parade is an excellent adaptation of the project Death Billiards,
It has an amazing story and each character has their own personality.
I love the opening (even though it might be a little too happy)
The writers leave a lot to the imagination of the viewers and with this anime, that works really well.
You uncover little pieces of the story yourself while watching.
Some of the characters stay a big mystery but the main characters go through a lot and you will see them evolve throughout the story.
If you aren't good with sad anime then this anime is probably a little too much.
I hope they will make a second season of this!