P.S English is not my primary language.
Anime is slow and depressing. 'I will finish it in one day or 2 days',don't think like. Because it has a dark atmosphere and its traceability is not that high. He clearly gives the subject and the message he wants to give, and he tells the stories of the characters beautifully (He also shows us the character development. For example Toboe). It doesn't leave much in the background (however you want to think of the final as open-ended). You can directly skip 4 parts of 30 chapters as a summary (chapters 15,16,17 and 18). I recommend it to those looking for something dystopian with a dark atmosphere. My score is 7.5 out of 10