These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Casshern Sins
Adaptation Displacement: This series is much better known in the U.S. and many Western countries rather than the 1970s anime it's rebooting, largely due to the fact that it was a centerpiece premiere in the US revival of the Toonami block.
Anti-Climax Boss: After Casshern loses to Dio in the penultimate episode, you'd expect a climactic battle in the finale, but no, Braiking Boss simply dies on his own instead of being taken out by Casshern.
Bittersweet Ending: Besides nearly everyone falling to Ruin and Casshern becoming death itself there seemed to be a strong possibility of Ringo and Casshern possibly repopulating the earth since both were made and heavily implied to be capable of creating life. They both could potential start a new race of very healthy human/robots and it would fit with the epilogue showing Ringo and Friender surrounded by flowers while she is at a very fertile age Casshern does say he will take on the role of death, but wasn't the whole lesson of the series was to show what would life be without death?
It's difficult to ignore the Messianic characteristics of Luna and her subsequent resurrection makes her very Christ-like…if whether she's helping the world or not weren't completely debatable.
The obsession of the robots with killing Casshern and eating his flesh, convinced that doing so will make them immortal sounds like a twisted version of the Eucharist. Likewise, the fact that drinking Luna's blood grants eternal life invokes Eucharistic imagery.
Uncanny Valley: Subtly employed in the designs of the more humanoid robots. When paired with the rare glimpses we get of humans, it becomes apparent just how eerie the likes of Casshern or Lyuze look with their stylized facial structures and perfect features.
Wangst: He has reasons to lament, but Emo Casshern might grate your nerves at times.