I'm a bit bored, so I'm going to do some of that continuity tiering I've been considering. As an arbitrary proof of concept, I'ma do the first ten episodes. As a basic guideline, the highest level is some direct reference to the events of an episode in a future episode, the next highest is the inclusion of something new that sees use later (whether character, ability, or object), then after that is an underlying plot continuation, then basic locational returns, and finally stuff that apparently has no bearing on continuity. It's a thing open to change, but this is just basic idea thingamajoggers. I'm going to only list the highest level thing, and also list the gap between the episode and where it's first referenced on that level.

Gem Glow: The centipeetle makes a complete return in Monster Buddies, 22 episodes later.

Laser Light Cannon: The red eye is directly referenced in Marble Madness, 42 episodes later.

Cheeseburger Backpack: The mission is the setup for the plot in The Test, 35 episodes later.

Together Breakfast: This is the first episode with the gem's rooms in it. I suppose one could consider Rose's Room a continuation of that, but I don't think that's a correct way to look at it.

Frybo: Pretty much just the introduction of Peedee.

Cat Fingers: I think this is the first episode with transformation, though it may be just be the first episode with Steven transformation.

Bubble Buddies: Connie and magic bubbles are here.

Serious Steven: Biggest thing here might actually be the expansion on the gem battlefield given in Rose's Scabbard, which may ascend to the level of direct reference in its importance, 37 episodes later.

Tiger Millionaire: The Amethyst inferiority plotline started here, and was continued in earnest in On the Run, 31 episodes later.

Steven's Lion: Here there be Lion.

Seems like a reasonable first run, though it could be more organized. There's a pretty high important thing introduction rate, maybe a higher one than could be expected.