So House Guest was kind of a short-and-simple episode as far as anything concrete went, but it was still able to raise a few questions.
The synthetic storm, again
Whatever conflict occurred on Earth may have been more destructive than was first indicated. The geode that the Crystal Gems want Steven to repair is built around a synthetic storm that is apparently quite large and releasing large amounts of energy. As mentioned in the implications post, this storm would have the potential to wreak devastation around the planet if not contained.
Could the storm have been the last gasp of an enemy seeking to kill off humanity out of spite, or a master plan to clear off the annoying planetary inhabitants? The geode, made out of stone, would have to have been put into place either as the storm was being created or being compressed by some sort of force field, so if the Crystal Gems were able to contain it against the creator’s wishes it wouldn’t have been easy unless the enemy was already beaten.
Perhaps it was created inside the geode with the intention of the containment being breached to use it as a powerful bomb later. That would explain why Garnet said there was “almost” an explosion (as they slid into a large blast crater—from an attack that may have been aimed at the geode?).
It’s even possible that the Crystal Gems created it themselves as an insurance method to ensure that the planet could be rendered useless to anyone should they come out as the losers in the conflict—maybe even as an aggressive negotiating tactic similar to madman diplomacy.
No matter where the storm came from, the Crystal Gems were unable to stop it themselves. A warp pad was installed so that they could monitor and maintain the geode containing the storm, preventing it from unleashing its power on the planet.
The nature of Steven’s powers
Yesterday we warned to be on the lookout for more information to be revealed about Steven’s powers later in the series: an awful lot was made of Steven’s reaction to seeming useless again, and the Crystal Gems themselves said his powers were fickle.
The most likely wrinkle is that Steven can best use his powers on things he cares about. His deep affection for Cookie Cats first caused his gem to activate; he cared about Connie, Lapis, and his father when he healed them (while what does he care about a big chunk of rock?); he deeply cared about the centipeetle when he bubbled its gem; and every time he uses his bubble shield it’s to protect someone he cares about. Even his misshapen cat body in Cat Fingers was only fixed with his father’s help, after realizing that the cat body would keep him from spending quality time with his father.
He’ll probably learn to use his powers on demand later, just as the other Crystal Gems seem to use their powers on instinct, but at this moment in the show he’s still young and so doesn’t have the firmest command of them yet; right now he can only reliably use them when it’s easy, which for Steven seems to hinge on having an emotional connection to the need to use his powers right then.