I will say this outright now. This movie doesn't have a happy ending. It's not meant to have a happy ending. And oh boy, do you need to be very ready for it.
It's hard to talk about this movie without spoiling anything, or hell, even the series in general is hard to have a conversation about to somebody new to it without something being spoiled. I'm writing this assuming you have finished watching the anime, the two movies before this, or reading the manga and are now interested in watching / have watched the 3rd movie.
The series in general is best experienced fresh, which is when you have little-to-no idea of what's the outcome. As such, I suggest you close this tab and get to doing one of the three things I had mentioned if you have yet to do so. Now if you don't mind being spoiled, read on but be prepared to be left in the dark about a lot of stuff.
Where do I begin? I won't be talking too much about the story, seeing as again, it's very hard to talk about it without spoiling anything. So instead, I'll delve into the theme of the story.
As mentioned above, the story wasn't supposed to have a happy ending. The concept around it feels rather... religious. I couldn't help but feel that the story is some sort of a weird retelling of the Bible and the genesis of God and Lucifer. Not that it's a bad thing really.
If you're familiar with Gen Urobuchi (the main writer of the movie), then there's a very high chance that you'll know his nickname, the Urobutcher. Urobuchi is famous for his dark storylines (Fate/Zero, Saya no Uta) with very bittersweet if not downright downer endings. But oddly enough, he wasn't responsible for the twist this time. That honor goes to Akiyuki Shinbo. Oh, how he one ups the Orubutcher himself is astounding.
The Rebellion's ending is depressing, yes. The ending can be unsatisfactory for a lot, yes. But did it work in terms of the story? Yes. I won't talk about it further as I'll be spoiling the movie, but I'll say this. There's a reason this movie was submitted to the Oscars. It's wonderful and seamless storytelling from beginning to end. Now if only the judges actually watched the movie and didn't dismiss it as a "kid's film".
If there's one thing I'll always give credit to Studio Shaft for, is that they always have fantastic production values. Both the audio and visuals of the movie are fantastic and are a step above from even their best works. The visuals have to be seen to be believed.
From well-chosen background music, to the heartbreaking themes of the movie, even closing your eyes and listening to the audio itself is a treat.
And I must mention the voice acting. Oh boy, the voice acting. Everybody does their role wonderfully, but someone rose just above the rest. Chiwa Saito, the voice actress for Homura, single-handedly steals the show from beginning to end. From Homura drowning in despair, to her slow descent into insanity, to her slowly realizing that she has become a *spoiler*. She just nails it.
Speaking of Homura... my god. It's no secret, Rebellion is all about Homura. I don't believe anybody would have expected this. Hell, she probably doesn't even deserve the shit that's thrown at her constantly. But it's inevitable. Gen Urobuchi's well known for creating idealistic characters, but always manages to break them down in one way or another by the end of the story. Whether they come out better or not depends on the material. Homura's development was something that nobody expected or wanted, but it feels so obvious and inevitable that more people should have seen it coming. And yet, hardly anyone did. The movie is called Rebellion for a reason.
When all is said and done, is it a masterpiece? Yes.
Now... did I enjoy it? Eh...
The movie itself is very heart-wrenching to watch, especially more so when you've seen most, if not all of the previous incarnations of the series (I.E. the anime, the previous two movies, the manga) and have grown attached to these characters, ESPECIALLY Homura and Madoka. After a certain point in the movie however, I couldn't help but shake the feeling that this probably isn't meant to be 'enjoyed'. It's hard to explain it in words, but that's how I feel about it. I personally probably won't watch it again anytime soon.
If you have seen any of the previous incarnations of the original anime and want to get some closure for the story, then you probably won't find much of it here. The ending still implies that there'll probably be sequels for it. But for what it does, it does it right. If you treasure the bittersweet ending of the previous incarnations and do not wish to tarnish it, then I suggest you stay away from this movie because Rebellion WILL destroy that small lingering light of hope.
At this point, I just hope Madoka doesn't become a cash cow franchise. It's such a waste of great writing and work by the Magica Quartet if that happens.