I was psyched to see the Centipeetele again, and it's good that she got a happy ending. But, my hopes for a Peridot/Lapis/Centipeetle alternate team are crushed.
In "The Return", while evacuating, Greg says something like, "In the end, your mother was only able to save a few of her closest friends. If it weren't for her shield..." I assume this means that Rose, Pearl, and Garnet were saved from corruption by hiding behing Rose's shield. Amythyst missed the war because she stayed in the ground too long, so she was probably uncorrupted because she hadn't come out yet. Or maybe the corruption is why she stayed in the ground too long, and is smaller than she should be.
In Lapis's flashback ("Same Old World", I think), we see many Homeworld Gems fleeing, then a something odd, I forget exactly what. This may have just been a major warp opening, or could have been the corrupting weapon. Lapis may be upset about spending all that time in the mirror, but it appears to have saved her from being corrupted.
Speaking of time: Zohar, we'd thought that the time Garnet mentioned in "The Answer" was significant for meaning the Gem war ended at year 0 of the Hebrew calendar. It turns out 5,730 years is the half-life of carbon, which may have been what they were going for.
When we first saw the explanation for the injectors, it looked to me like they were sucking the life out of organic material. One of the chibi shorts had Amythyst talking about sucking up the "good stuff" to make Gems, before being interrupted by Pearl, like she's trying to protect Steven from a harsh reality. All in all, I'd say the Kindergardens need to drain organic life in order to function. The site of the Kindergarden is still barren millenia later, it appears to be pretty damaging.
I wonder if Peridot could use her Certified Kindergardener skills to draw just a little life force, maybe from an invasive species like kudzu, to fix the corrupted Gems?