Tōka Gettan

Something weird and fascinating is going on, but our brains are melting just trying to make sense of it all. There's this boy, you see... only (s)he might be a girl, and there's this world, or this collection of worlds, and... oh, heck, check back again after we finish assembling the Jigsaw Puzzle Plot.

Provides examples of:

Absurdly Youthful Mother - Yumiko.
Adult Child - Yumiko.
And Knowing Is Half the Battle - the first available Fan Sub version of this series practically inundates viewers with "educational" translation notes.
Back to Front
Big Eater - Momoka Kawakabe.
Bleached Underpants: It's based off an erotic visual novel.
Brother Sister Incest (inter-generational... er, sort of)
Catgirl - Kaya and Yurika.
Christmas Episode - Episode 9.
Clothing Damage - seen in one episode due to fish attacks, being immersed in water, and being magically made out of rice paper. Also seen in another episode where a character gets whipped and suffers this trope.
Creepy Twins - triplets to be exact. They seem to have a hive mind.
Crossover - Episode with Yami to Boushi To Hon no Tabibito characters visiting, for extra Mind Screw.
Deliberately Monochrome - most of episode 21.
Dreaming of a White Christmas - Invoked via Your Mind Makes It Real.
Drives Like Crazy - Shouko.
Elaborate University High
Every Car Is a Pinto - Every car Shouko Rokujou drives certainly is, particularly the one involved in the spectacular explosion in episode 9.
Fan Service - and no shortage of it, either.
Fun With Subtitles - In episode 25, one character believes that the subtitle displaying his name is wrong, and insists it be corrected.
Gender Bender (or Wholesome Crossdresser)
Go Go Enslavement - Most of Yurika's screen time is this.
Gratuitous English - probably the best example is Nene telling Ken-chan to GO TO HELL!!
Gratuitous Italian - Makoto uses this a lot, including many musical terms.
Groundhog Day Loop - Only noticed by Makoto.
Growing Up Sucks - Yumiko wants to go back to high school.
Honorifics Makoto uses some unusual ones, like "Tou-chan-senpai."
Hot Mom - Yumiko, all the way.
Immortality Nene and Kaya appear to have this.
Jigsaw Puzzle Plot - To make sense of the plot, watch episode 26, 24-1 and then 25. That's right. You have to watch the series backwards to make things fall into place.
- Alternatively, watch it forwards numerous times.
Meido - Nene
Mind Screw - on the first viewing, it's pretty much guaranteed that you'll have no idea what's going on for the first six or seven episodes, whether you know it's in reverse chronological order or not. Those who first tuned in before the backwards airing order became well-known were even more confused.
Noblewomans Laugh - when those triplets do it, the effect amplifies.
No Periods Period - averted in the case of Makoto Inukai, who gets her first at the rather late age of 15.
One Steve Limit - With a list of names including Yumiko (writer), Yuriko (Yumiko's mother), and Yurika (vampire catgirl), you'd think the writers were deliberately trying to flout the limit.
Our Vampires Are Different - the lesbian catgirl variety, to be specific.
Parental Incest - Manages to include the Squicky and non-Squicky varieties.
Power Perversion Potential - triplets (all the time they aren't playing pranks) and the author lady (sometimes).
Replacement Goldfish - the character we know as Touka Kamiazuma is a replacement for Yumiko's daughter, who died in childhood because she couldn't handle the power of the stone sword.
Shrines and Temples
Short Titles - Every episode title is a single kanji character, and all but one of them can be represented as a single word in English.
Single Target Sexuality - Shouko, towards Makoto.
Spin Off: Originally, a planned title for Touka Gettan was Moonlight Lady 2.
Third Person Person - Makoto Inukai, as well as Yumiko Kamiazuma.
Widget Series
Yaoi Fangirl: The triplets.
Your Mind Makes It Real: Yumiko's powers.
Zettai Ryouiki - several characters, but Yumiko deserves special mention for achieving the look with a long sweater and thigh-high stockings.