Art Evolution: While the Prince and his cousins always have Black Bead Eyes, in the early strips, they're the same shape, size and style as seen in the games. Over the course of the first plot arc, however, their eyes gradually start getting drawn bigger. Compare the first strip to this one.
As You Know: For some reason, the Future!Prince feels he has to explain to himself how their cousins hang out on the Space Mushroom.
He also recaps the plot of Katamari Forever as they're flying off to save the world... until he gets to the part they aren't aware of: that The Bus Came Back for RoboKing, and he is NOT happy.
Bad Future: Future!Prince claims to be from one that's just three hours after his arrival.
Michiru Hoshino, after her family's falling Out of Focus following the original game, reappears in the UFO arc and continues to be a supporting character when needed.
During the Future!Prince arc, the RoboKing reappears as well.
After being Put on a Bus at the end of the UFO arc, Daisy returns in the Journey to Cow Planet 2 arc.
Calling Your Attacks: "SUPER PATENTED ACE EVASION TECHNIQUE: ACTIVATE!" (Which turns out to be the same sort of backflip the Prince used against him in the first arc.)
Can't Get Away with Nuthin' : When the Prince knocks over a lamp, the King's right behind him and immediately starts guilt-tripping him over it.
Chekhov's Gun: Sharp-eyed readers may notice the Present the Prince rolls up during the UFO arc; this comes into play later.
Cloudcuckoolander: The ever-cheery June is more concerned with chasing butterflies than paying any attention to a tense confrontation between cousins, and manages to entirely miss being led through a hallway of lasers.
Color-Coded for Your Convenience: Everyone's speech bubbles have different colored text and backdrops in order to make it easy to identify who's speaking. Even the Future!Prince has a very distinct shade of green, much lighter than the Prince's.
Cool Shades: Ace has a pair of these, which he randomly whips out to try and look cooler.
Deliberately Monochrome: When the Prince and three of his cousins visit Cow Planet 2, the atmosphere is all black, white and greyscale, with only the Prince and his cousins providing a Splash of Color to the landscape.
Did Not Get the Girl: A story arc revolves around the prince trying to help a man reconcile with his girlfriend by making a katamari that shows off his affection for her. While she's touched by the gesture, she gently lets him down that she isn't interested in pursuing the relationship.
Flying Saucer: One's heading toward Earth at the start of the strip.
Fun Size: Kawaiiko Ichigo invokes this by staying even smaller than her already tiny cousins.
Go to Your Room: The King starts to tell the Prince this right at the very start of the series, but gets interrupted by the plot.
Gone Horribly Right: The Bad Future was caused by this: the RoboKing's Automatic Katamari was meant to revolutionize katamari by drawing things to it, removing the need to roll around. Unfortunately, it turned out to be a tad too strong.
King of All Cosmos: We cannot imagine being so reckless around something so precious.
After learning about the UFO stealing all things bovine-related, the King proclaims they can't allow anyone to simply 'careen around the planet, take anything they see, and return to space with it.' Then immediately orders the Prince to do exactly that.
Ironic Echo: When Odeko explains about the literal black hole, he finishes with "You know. Science." Two strips later, Opeo explains why he felt safe in letting go of his katamari, and ends with "You know. Science?"
It's All About Me: Ace would sooner see the UFO escape entirely than let the Prince save the day.
Laser Hallway: One of the obstacles the Future!Prince needed help getting past; specifically, the lasers are invisible, so he uses June's ever-constant raincloud to make them visible long enough to work their way through.
Look Over There: Done by Ace to the Prince off-panel in Thanksgiving on a Roll. During the period where the Prince was distracted, his plate 'mysteriously' broke.
Monochrome Past: When explaining to Ichigo, Macho and Odeko what happened at the end of the UFO arc, the panels are cast in sepia tones.
Motive Decay: The aliens freely acknowledge this when explaining their actions, as by the time they realized they weren't rescuing other survivors, they were too caught up in collecting everything cow-related to care.
No Time to Explain: Rather than immediately explain what big threat to the Great Cosmos is arriving in three hours, the Future!Prince rushes his past counterpart off to start recruiting help. (He won't explain on the way, either.) It's not until they've gathered their party that he's willing to Info Dump.
Not So Different: The Prince tries to reason with the RoboKing by pointing out that he knows what it's like to be in the King of All Cosmos' shadow.
Papa Wolf: The King may not be a model father by any means, but when he sees his son in distress...
Pie Eyed: The Prince's eyes are drawn like this a couple times in the early strips.
Plot Tailored to the Party: The Future!Prince inverts this by gathering up cousins with the specific talents he feels are needed to save the world. (Naturally, this gets complicated by Ryu's absence and Ace showing up.)
When the Prince recieves a 'coded message' that he can't understand. Given the circumstances, you'd think that Daisy would've written more than 'moos', but they didn't, and as a result he doesn't know what he's getting into until it's spelled out for him.
The King becomes a victim of this several times in a row, causing him to think that he's 'out of touch' and no longer needed.
The Resenter: Ace thinks the Prince always gets to save the day and get all the glory for it, so when the King calls him in to help with the UFO problem, he's eager to outshine the heir and be hailed as the hero instead.
The Rival: During the UFO incident, the King brings in Ace as backup and extra insurance 'just in case'. The deck's also stacked in his favor via a much bigger starting katamari.
Unknown Rival: Not to his cousin, but to the public at large... at least, that's what Ace believes.
The Future!Prince eventually reveals that his father has these: turns out the way he found about about the crisis he had to Time Travel to prevent was a PS on the letter he sent him. The King spent more time talking about the Present than the RoboKing.
During the Black Hole arc, Opeo's more interested in bringing the Prince back than the crisis at hand...
Something We Forgot: After the aliens are dealt with, the King mentions how everyone's ended up right where they should be. Save for Daisy, still stuck with all the cows.
Stable Time Loop: After they successfully stop the Robo-Katamari, the Future!Prince uses the time gate to try and avoid a paradox, even if it means he'll be repeating the same small period of time over and over again.
King of All Cosmos: Ace is here as insurance. It's not that We expect you to fail. Why would you think that?
Suddenly Voiced: In the games, the Prince and his cousins are Heroic Mimes; they could talk, but the player couldn't understand/hear their voices as more than Pokémon Speak. In the comic, their dialogue is readable.
Future!Prince: "The chances that something unexpected might interrupt our departure are essentially zero. Yes, it's so still and quiet out here in these woods. There's no way there's anyone around who might stop us from saving the world. To reiterate, we'll be leaving immediately, and I foresee us encountering no problems. Something would have to interrupt us right this second for our departure to be prevented. So, on that infallible note, let's- Ace: "Hold it, Prince!"
Odeko accidentally does this again in a later arc:
"The Reason You Suck" Speech: Ace tries to give the Prince and Future!Prince one in Called Out, but it doesn't work too well given how he doesn't understand the situation or his cousin's nature at all.
Tiny Tyrannical Girl: Ichigo only comes up to the Prince's waist, yet easily bosses around her cousins.
Unrealistic Black Hole: Lampshaded and Discussed during the Black Hole arc. Ichigo protests when Odeko calls a phenomenon a 'black hole'; he clarifies that he means 'a hole that is black', and how it's completely different from a traditional black hole.
Odeko: You know. Science.
Walking Techbane: Surprisingly, Opeo turns out to be this for one simple reason: he's somehow contracted a computer virus.
"Well Done, Son" Guy: As always, the poor Prince finds himself being compared unfavorably to his cousins.
Your Size May Vary: The King's ability to change size depending on his mood and atmospheric conditions is still present. As a result, he doesn't look that much bigger than the Prince when the UFO passes overhead.