Chapter 2, p. 19-23. Keima has a nasty feeling Elsie's a Lethal Chef. A double subversion: at first it looks like Elsie's cooked an Alien Lunch... then the reaction kicks in and Keima finds himself running for the toilet.
While following Mio (chapter 3, p. 20):
Keima: It's kinda troublesome to locate a house in the real world. There would usually be an icon on the girl's house.
Elsie: What do you mean, 'usual'?
Mio realises she's in a Cinderella story: "I should have realized the meaning of that pumpkin-shaped bicycle for today!!" (chapter 5, p.2)
When Elsie realises she can track Kanon through her spirit sensor: "You should have told me earlier." (The anime renders it as "You should have remembered that earlier, you brain-dead demon.") (chapter 10, p. 5)
Elsie lampshades (chapter 13, p.13):
Keima: If she [Shiori] is half-hearted, I will send a complaint letter!!
Elsie: To whom...?
Another from Elsie: "As always, you aren't scared to say things that can easily bring down the reputation." (chapter 14, p.14)
Keima starts gloating about finally hearing 'the voices of the heart'. Elsie points out "You know... you were only told 'Stupid'." (chapter 14, p.18)
Discussing the cause of Shiori's gap (chapter 15, p.5):
Elsie: Maybe in truth she wanted to talk more.
Keima: I don't want that kind of conventional librarian.
Elsie: Who do you think you are, Kami-sama?
Keima on the runaway spirits' intentions: "I'm so disappointed about it being unexpectedly easy. There's little foreshadowing, little amount of weird proper nouns..." (chapter 24, p.5)
"Your story already ended!! At least lengthen the gap a bit more! Get out!" Keima rants when Haqua reappears. (chapter 27, p.5)
Keima on Haqua ignoring his protests: "This conversation is on the '90s girl game level! I can't take it anymore!" (chapter 27, p.6)
The Capturing God is not happy with the terms of his contract: "With a task like this, normally, you only need about 7 pieces. Imagine 60,000 D-gon balls!! Or 60,000 chambers in the Shaolin Temple!! Who'd be willing to do that!!" (chapter 28, p.5)
"Look at this school. Even though in games, schools have aliens, military and electric waves, those kinds of idiosyncrasies, in real schools there is only so much as one hair color!!" (chapter 28, p.7)
"What's up with those half-way parameters? She's exactly a middling girl among real girls..." (chapter 28, p.12)
Keima really doesn't like Reality Ensues: "If they made a game like this, the company that made it would burn!!" (chapter 28, p.16)
Talking to Nikaido about Jun Nagase (chapter 39, p.15-16):
Keima: I see. You're not telling me about Nagase, because it includes something you don't want to say.
Nikaido: What do you mean 'I see'? What are you basing this on?
Keima: That happens a lot in games.
Keima on Haqua and Yukie's relationship: "It's like a drama..." (chapter 48, p.13)
Lampshading Compulsory School Age: "It seems like he repeated school, and now he's in the same class as his sister!" (chapter 51, p.5)
How Elsie got the idea for a Light Music Club (chapter 54, p.7):
Elsie: An anime I watched at night was using a classroom for practice.
Upon receiving the letter from the editor-in-chief, Keima complains "What's with this backstage blabber? It's like something out of the 80s!!"... then goes on to grumble about the editor-in-chief's treatment of the author. Haqua proceeds to lampshade the hypocrisy. (chapter 94, p.6)
Keima: H-huh? I feel like I've been dreaming for a week...
"I'm again put behind the scenes..." Elsie moans. (chapter 96, p.5)
Keima has a point: "That I would really approach the real world on my own is a big deal." (chapter 102, p.13)
"That we have to go together... isn't this just like a capture operation?" (chapter 102, p.18)
Keima wonders why Elsie would want to go on a ferris wheel: "Is this really interesting for you, despite your ability to fly in the sky?" (chapter 103, p.8)
"The third time in this month... How often do I need to come here?", Keima remarks, on yet another visit to DezeniSea (chapter 105, p.16).
On having to interrogate Keima's previous targets (chapter 108, p.6):
Keima: Besides, it's strange to continue on like this, despite having finished the capture and seen the ending! It's normal to return to the menu after you're done with the capture and everything is reset! This is such a shitty game!
Elsie: Which 'normal' do you mean?
Chapter 112, p. 10:
Keima: I have seen a mountain of patterns like this one. In games.
Akari: That's also just an empty theory.
Keima on the basis for his latest theory (chapter 119, p. 5):
Keima: Two is more than enough! If you look at history there is plenty of precedent for that! In games.
Haqua: (thought balloon) He's really the sort of guy that only comes up with those lines.
Chapter 122, p. 18: (thought balloon) At least use different lines!!
Haqua says what we're all thinking (chapter 123, p.6):
Haqua: It wouldn't be strange for you to get killed once they realize that you were five-timing them.
Keima: Hey, don't make fun of it!
On Haqua's unfamiliarity with a cellphone (chapter 125, p.12):
Haqua: I borrowed it... but I have no idea how to use it.
Keima: She's a devil and yet she's full of ideas about how to interact with humans...
The power of Keima's latest event (chapter 126, p.4):
Keima: Just wait and see. With this event, I will raise each girl's love points by 5!!
Haqua: How much is 5 points?
From Shiori's novel (chapter 128, p.9):
Pierre: Simone, you're like the main character of a story.
On Keima's Determinator nature: "This man just doesn't give up, even when I threaten him… He doesn't even flinch…" (chapter 135, p.14)
Keima sizes up a captive: "I just hope that you're not some underling who nobody cares about." (turns to Nora) "As it stands, it should be very safe since she's just a clumsy moe girl." (chapter 137, p.12)
Lampshading an invocation of Bridal Carry (chapter 137, p.13):
Vulcan: I cannot move...... Carry me.
Keima: Just return to Tsukiyo and walk!!
Lampshading Webcomic Time: "It's only been three days, but it feels like we haven't seen each other for mooonths." (chapter 137b, p.5)
Nora knows how Keima can solve things (chapter 138, p.8):
Nora: Goddesses grow stronger with love, right? Isn't that your specialty?!