- The game Karen played as a kid, Kiramira, is a parody of Pretty Rhythm/PriPara/Kiratto Prichan (same concept of using cards to collect "coordis" (outfits). The handheld toy she had looks a lot like the PriPass Idol Link

- When Karen is at the Mister Donut/McDonalds with her friends, they're there to fill out their guidebook booklets for an upcoming school trip. Students often work together as a class to create the booklets, ie everyone draws an illustration for the cover and they vote for the one they like best, and sometimes students help create the itinerary. But it looks like they were just filling in their own booklets that they had received (the one on the table had some notes about what to do in a free period).

- The universities Junna listed in her wishes are all parodies of universities in Japan:

1. Kusainada University = Waseda University (by removing the very top part of the first character 草 (kusa, grass) in Kusainada 草稲田, you get Waseda 早稲田.)
2. Nissho University = Nihon University (日正/日本, 正 and 本 can both mean real.)
3. Tama Arts University = Tama Art University (they only changed the kanji for "Art" here (藝術 geijutsu/美術 bijutsu), so... it reads differently in Japanese, but kind of hard to reflect in English.)

- Not important, but one of the panels on Kaoruko's dekotora says "仁義" (jingi). I translated it as morality, but the origin of the term is "humanity and justice" of the 5 Confucian virtues, and it's used as a greeting among gamblers/yakuza as it's part of their moral code.

- The version of shogi Maya is shown sucking at is doubutsu (animal) shogi, more specifically gorogoro doubutsu shogi.

- Hanayagi-maru and Isurugi-maru are the names of their trucks. I think the maru suffix comes from a naming convention for ships, and I believe most dekotora have it in their names

- Hanayagi Suisen 彗仙 is the name that Kaoruko inherits. 彗 = sui = comet, 仙 = sen = a person of exceptional talent (also sage/hermit/immortal.)