I'll start with a warning: there was no way for me to properly review this dorama and explain why I loved it at first and ended up hating it (and believe me, I don't use this word lightly), without some spoilers.
So, before you keep on reading, let me ask you a question: have you watched "Full Metal Jacket"? If you haven't, then maybe play it safe and stop reading. But if you have, here's one more question for you: would you say that Sergeant Hartman was a fine educator or a rotten S.O.B.?
If your answer is the former, then stop reading and start watching this dorama, there's a high chance you'll love it! But if your answer is the latter, then you might want to keep reading - spoilers included - so as to avoid wasting 9 hours or so of your life (over 12 if you include the SP) on this.
And now I'll proceed explaining why I think so (spoilers from now on, consider yourselves warned):
I was captured right away by the thought-provoking premise, and it kept me thinking and (probably over-)thinking for the first few episodes. I even thought, for a brief moment, that maybe the scriptwriter had had an incredibly prophetic view of his future (and our tragic present), thus using this dorama's distopian classroom to portray a society where those in charge seem to have loads of evil fun pitting us "commoners" against each other and even unleashing chaos - the only thing they care about being that we obey, don't think and follow their rules which are more and more absurd each day - and clearly counterproductive, at that. Ok, I was seeing too much into it, LOL, but that's just to show you how intrigued I was!
Slowly but progressively, though, the story kept getting sillier and sillier with every episode. Short after the middle of the series, I started suspecting where it was heading: to an utterly insulting ending where they'd say that this monster (Amami Yuki's character couldn't deserve titles like "teacher" or "educator", and sorry if you disagree, but this is my informed opinion as someone who's worked in this field!), I repeat, where they'd say that this monster had actually been a "good (hell, even great) teacher", that it had all been just some "tough love" and that it had all "turned out well after all".
And that's where I started hating it.
Because I believe that if you treat people badly (Akuma-sensei - sorry, Akutsu-sensei - pun intended - traumatizes her pupils day in and day out, and her behavior sums up to psychological torture in my book!), I repeat, if you treat people this badly, no good *whatsoever* could *ever* come from that. To even imagine such an idiotic development is total BS, sorry.
If you treat people like this, some bad sh*t is bound to happen instead! Just like with Sergeant Hartman and Private "Gomer Pyle" in "Full Metal Jacket", you know...?
Approaching the end of the series, each episode unfortunately confirmed my suspicion, and I was more and more disappointed, and then really *disgusted* by the lousy, idiotic last episode (*every single scene* of it felt like an insult to my intelligence: the commercial-like family scene, the fight with the punks - nani sore?!? Where the hell did those crawl out from? A Chuck Norris movie maybe?!? And then again, the 180° U-turn from monster to ideal teacher / hero, even lecturing the kids on how it's wrong to hurt others - true, of course! But....how dare *she* say that?!? You gotta be f***ing kiddin' me, c'mon! And I could go on and on but I guess you got the picture...in one word: "BAAAAAAAAAAAAAAAD!!!").
After watching Arimura Kasumi no Satsukyu" I had felt...cleansed, that's the word!
After watching this series to its end...I feel like I desperately need the soul equivalent of a long, warm, scrubbing-all-over shower! Such a terrible feeling it has left me with!!!
The acting was good (I mean, the kids' acting, as Amami Yuki's character being the expressionless monster she was, the poor actress couldn't show her acting skills, unfortunately. And the rest of the cast, alas, were little more than extras, so it's hard to judge them - except to praise Kaho for her adorable "onee-san"). The music was okay. I'll go with a 4/10, also considering that to correctly asses the "rewatch value" I'd need negative numbers...