Ass Kicking Pose: Reimu and Marisa actually strike one of these in a recent chapter... only to find out that the person they thought they were rescuing wasn't impressed.
Battle Couple: Ryan and Utsuho, Aka Solar Team, are well on their way to becoming one.
Berserk Button: If anyone other than the SDM staff calls her China, Meiling becomes absolutely furious.
Energy Absorption: Ryan's power. It allows him to absorb pretty much anything energy-based. Also counts as...
Elemental Absorption: Since he is capable of absorbing things like fire, lightning and danmaku bullets.
Actually, lightning is the number-one thing Ryan wants to avoid. As a Mega Man expy of sorts, he is weak to electricity like the classic Mega Man himself—specifically, his muscles seize up, inducing paralysis. Subverted hard in the case of danmaku bullets, as they still cause pain regardless of absorption.
Sparky is a good boy come the struggle against Flandre in the SDM's basement.
Failed a Spot Check: During Marisa's battle against Cirno, she begins shooting off repeated Master Sparks. She stops firing after a while to take a breather, but finds out that the one tree that wasn't blown up was where Cirno was hiding.
Hearing Voices: Ryan calls it his Common Sense. Utsuho has one as well.
Chapter 16 and later in 22 reveal that the voice in Utsuho's head is that of the lingering Yatagarasu, who has -for whatever reason- decided to stay inside of Utsuho and act as her instructor.
Ryan's voice inside his head is actually, as it turns out, not -entirely- an insanity. See Which Me? below.
Hong Kong Dub: In-universe, due to messing around by Yukari so the English-speaking Ryan and Japanese-speaking Gensokyo residents can understand each other.
I'm Cold... So Cold...: Although he doesn't actually say anything, Ryan gets this in Chapter 26. He manages to recover in time to make an awesome comeback.
Ryan's thoughts: You know, I like this, I really do. These two have been real accommodating, and are very friendly overall. Already, the idea of living in Gensokyo is appealing to me, even Common Sense is giving the thumbs-up! Although I should probably find some bros…waitaminute. Something Reimu mentioned is coming back.
Ryan: Ah... Marisa...?
Marisa: Hm? What's the matter with you?
Ryan: Reimu did say before, after we were working... something about the guy-girl ratio in Gensokyo?
Marisa: Ha! Yeah, you're totally an endangered species, ze. *Ryan headdesks* Hey, at least you've plenty of options for shacking up with someone. They'll probably be more willing than you are to get together, considering the limited options. *headdesk* Especially if you're gonna be a fighter. No guys in Spell Card battles till now, ze. *headdesk* Real quick! If you're thinking of getting with a youkai chick, my advice: don't get frisky in the Spring, ze. *headdesk*
Reimu: Marisa, I think you've messed with the poor boy enough. *Ryan starts to sit up* Although, that last one? Really keep it in mind. *headdesk*
My Name Is Not Durwood: Suika calls Ryan everything except his name. Also, Alice Margatroid is understandably annoyed when Ryan calls her "Metroid" the first time they meet.
Obfuscating Stupidity: Yuyuko, just...Yuyuko. Think she's all whimsy and simplicity? Think twice.
Oh Crap: When Cirno brings up that she beat Marisa.
And when Ryan realises just who knocked out everyone in SDM. Hint: Flandre thinks Ryan looks tasty.
Phrase Catcher: "Goddamnit, Yukari!" gets bandied around a bit.
Schedule Slip: The six month hiatus was humourously Lampshaded in the "Intermission" chapter.
Sempai Kohai: Once Flandre and Utsuho meet, it doesn't take long for the former to start referring to the latter as "Okuu-senpai".
Shout Out: Ryan's powers make him very comparable to Zero. (The gun and sword combo being reminiscent of the Mega Man Zero titles does NOTHING to help.) This is lampshaded by Yukari, much to Ryan's embarrassment.
Yukari: Dr. Wily does not approve.
The Champion: Ryan has shown shades of trying to be this for Utsuho's sake. Only succeeds once in a blue moon, however. Primarily during his first encounter with Chino, in the knowledge that he'd attempted to assault Utsuho for rejecting his offer to join the villains of the second story arc.
There Was a Door: When told to assist Patchouli in her first appearance in-story, Sakuya attempts to stop time and exit through a window. Remilia stops her and directs her to the door instead.