The scenery in Island Adventure was fantastic, as was the interaction between the characters. What did we learn about Gems, though?
It appears that Sadie’s fish-murdering skills transfer over quite effectively to Gems—the mindless monster Gems, anyway. Using nothing more than a sharpened stick and maybe a one- or two-level dip into Awesome, Sadie is able to fight against the monster the Crystal Gems had been looking for, defeat it, and kill it.
This is the second time we’ve seen a Gem – a group that, as a whole, can take massive hits from blunt weapons – get killed by a piercing weapon. Of course the first time it happened it was with a real sword, and the killer was able to cut through a tree trunk with a balloon sword, so this is the first time an actual vulnerability can reasonably be inferred.
As we’ve observed on our page about the capabilities of Gems, there is a lot of variation in how powerful the Gems are depending on the needs of the scene. It may have been more believable if Steven had fought the Gem alone, but the episode wasn’t about him so he really couldn’t be the one to do it.
Just because we understand why the writers made the decision they did doesn’t stop us from looking for an in-world explanation, though. We’ll speculate on that later, but right now let’s just watch out for any more instances of Gems being defeated by piercing attacks.