Spinel is the best villain Steven Universe has given us! She has a heartbreaking backstory, an intimidating appearance, personality, and set of powers. And a devious voice. She's also very identifiable, and you understand why she's doing what she's doing. She's also really funny! Her opening song is simple yet very catchy and memorable! And her backstory song cuts you deep. I almost teared up myself. Top all of this off with a dedicated performance from the talented Sarah Stiles and you got yourself a perfect villain!
Apart from Spinel, this movie doesn't really improve upon anything else. It still has the great voice acting, funny comedy, catchy songs, memorable characters, intense action, and beautiful animation we've all come to know and love.
The series is a prerequisite to watching this movie, however. I highly encourage you to do so, it's pretty great. I have some issues with it but... yeah. Go watch it.
