I saw this video recently; it has a little bit of background about Spinel’s design, along with a tie-in to a song from Adventure Time.
[spoiler]I’m still not sure how I feel about the all-musical format. And as much as I liked seeing glimpses of the ‘rebooted’ Crystal Gems (Pearl’s formation was very interesting!), once the solution to the problem became obvious, a lot of the dramatic tension seemed to disappear.
I wish they had spent a few episodes leading up to this to show more of what happened after the last season finale; the time jump was a little too jarring for me, as was the Diamonds returning to their adoration/worship of Steven (still seeing him as Pink, in a way).
The Steven and Greg fusion (“Steg”) was unexpected!
Little Homeworld was cute; I wish they had shown it being rebuilt too.[/spoiler]