I really liked the new villain. As usual, Steven Universe somehow managed to portray its characteristically complex interactions, relationships, and emotions in a very accessible children's medium. In most shows it's easy to think of a character like that as disposable and forgettable. Then she's destroyed and it's pretty devastating because we realize that the character is three dimensional just like a real person. It is made even clearer just how selfish Pink Diamond was (though I hope they depart from this topic and find new plot points outside of her closet full of skeletons, because I feel like the character development of Pink/Rose as a major focus has run its course). Spinel also does not quite come full circle in personality, which is usually an annoying staple in cartoons. It is clear that she will never be the same again, but that she is going to try to heal.
We got to see a stark side-by-side comparison of the Crystal Gems' current states with their original "configurations." Amethyst was particularly tragic because we could see just how clueless and aimless she was when she appeared hundreds of years after the war she was supposed to fight in.
But I thought the plot itself was sloppy. Where did Spinel get all of that crazy-ass equipment and how did she get so powerful in such a short amount of time? They set the stakes so high with the injector, rivalling The Cluster in its scope and urgency, only to brush off the failure to keep it controlled as a minor inconvenience in the end. They shouldn't have blown up the whole thing, because it cheapened the climax of the movie.
I'm not sure how I feel about Spinel going off with the Diamonds. It seems befitting on the surface, but when you think about it, it totally contradicts the resolution to start fresh. The Diamonds want her be the "new Pink," and Spinel is eager to slip back into the role of jester/toy servant. It just seems like wish fulfillment with the same old toxic dynamic on the horizon. Hopefully they will continue to develop this rather than just using it as a write-out because they didn't want to deal with her being in the main crew. I'd like to see how this pans out, in the high quality writing the show is known for.
The movie doesn't really set up a great segway into season 6, since apparently they are going to make a season 6. It sucks being an adult viewer because I have a hard time accepting that everyone was super chill about this sudden regime change, including the Emeralds and other gems who inevitably benefited from the status quo.
Overall I liked the character driven stuff, and I enjoyed the movie for what it was, but it felt pretty disjointed from the main plot and in a way, I would have been happier if they just ended the series at season 5.