Deca Dence is a combination of many things - post apocalyptic battle for survival to begin with... however it's best to just watch that 2nd episode to begin to wrap ones mind around what is actually going on. The world building is very complicated, but the story itself is revealed in a pretty straight forward way - to the point that fans of anime will settle in quickly. However, if this was the first anime someone ever watched? I think it could be truly profound, just due to the radical nature of content compared to the average TV show.
Id say Deca-Dence is built first on entertainment. Characters are iconic and fun. Action sequences are frequent and well presented. Drama occurs when it needs to, and unfolds in logical ways that fit character motivations.
I really like the opening theme, to the point I watched it every time. Credit song is also memorable. All the audio is solid, from voice acting to general soundtrack.
The 12 episode run is pretty spare - with very little filler/flashback. Even when that does happen, It works so well with what is happening in the story, I completely approve. I got the feeling that the creators were trying to squeeze everything in, as opposed to extending moments - and that is my type of anime! I want dense content devoid of fluff.
A lot of the technology descriptions and anime style has a simplified look that some may not appreciate. I'd loved it myself - and with a little jump of creative logic, these stylistic choices could be viewed as symbolic gestures that get to the heart of character and story first - as opposed to dwelling in technical description. It is an anime after all! And dialing back production choices for content related reasons... to me? Is a sophisticated approach to story telling.
There are some questions that if asked, really don't have meaningful answers - most of this would be regarding the crazy hierarchy the characters exist within, and how these 'levels' of individuals interact. But? That is really only on analysis - the nature of how everything unfolds? Follows consistent pacing that kinda prevented this viewer from going down those mental paths.
Who would like Deca-Dence? Most general fans of anime, I suspect. Otherwise, fans of large scale action sets involving monsters fought by teams of people. Fans of movies like the Matrix or other cyberpunk literature: early William Gibson for instance. And fans of action movies, like the Professional or the Enforcer, that have
strong mentor/student relationships along with all the action sets.
All time, top 5 anime? I don't think so, but I wouldn't debate someone who did. While I don't think it is in the same class of a Steins;Gate, Deathnote, Cowboy Bebop, Neon Genesis or Code Gaess - I would put it damn near in that same league. There are all time anime that I like Deca-Dence way more that (like Fullmetal Alchemist Brotherhood or Escape from Titan). I would never try to tell anyone it is better than those epic experiences, I just personally like Deca-Dence better, because I think it's run is more fun and entertaining.
Deca-Dence is an elegant 12 episode run, where every episode is good. I'll likely kinda fit it in with other anime like that: Hinamatsuri, D-Frag, Juuni Taisan - as a few other examples of single season anime that are good all the way through.
