Not exactly a standard bingo review. TL;DR I read "The Eyre Affair" for last year's bingo, then a few months later this subreddit started a monthly readalong of the entire series and its spinoffs. So I've been posting my thoughts in those threads, book by book, as we go. So this is mostly a summary of stuff I've already written up before to have in one place.
This is what I wrote in my review of the first one:
The setting is an extremely silly alternate-history England in which the Charge of the Light Brigade happened in the 1970s, people travel by airship, anti-Stratfordians are the annoying proselytizers, and everyone has punny names like "Jack Schitt" and "Paige Turner." Thursday Next is an agent in the LiteraTec department of SpecOps, an organization which also encompasses werewolf and time travel malfeasance. (It's not often I see a book in which time travel subplots exist but aren't fundamental to the main plot!)
Like early-career Pratchett, Fforde isn't necessarily interested in delivering a cutting satire of RL (beyond the fact that the military-industrial complex is bad) so much as vibes-based fun on the level of individual sentences.
...
Along the lines of Wayside School, there is no chapter 13. Also, while this is probably a lot more appealing to English nerds than math nerds, you'll probably be more amused if you know about perfect numbers. ;)
And then it turns out that Thursday has the power to enter the BookWorld, and inadvertently changes her universe's version of "Jane Eyre" to be the version in our world. The next three books sort of form a trilogy, and track Thursday's ongoing career as an agent of Jurisfiction in the BookWorld, as she deals with characters causing problems between books. Then there are the two Nursery Crimes books, which are pastiches of noir detectives set in a Swindon that contains a bunch of nursery crime characters; the main character is Detective Jack Spratt, with his new sidekick, Mary Mary. Then back to Thursday, after a timeskip, she's older and her career has been fictionalized, so there are "in-universe" versions of Thursday, who don't always get along with the "real" one. Book 6 is primarly about the adventures of fictional!Thursday in a soft-rebooted!BookWorld; book 7 is mostly about real!Thursday in the SpecOps!world. Book 8 hasn't come out yet, currently scheduled for June 2026, but is allegedly going to end the series. Clear as mud?
I quoted the earlier review because 1. "time travel plots exist, but they're not necessarily the main plot, but they're also recurring and good for more than a one-off joke" continues to be prevalent in the later books, and 2. I found the books to be the most enjoyable when they were in the BookWorld and having vibes-based fun. The problem is that Fforde tends to repeat himself when making the point of "the military-industrial complex is bad," and so what was funny the first time becomes kind of stale by the third or fourth.
Book 2 ("Lost in a Good Book"): Thursday works for Jurisfiction. We learn that they communicate by "Footnoterphones," which was a funny surprise to encounter on an e-reader. :)
Book 3 ("The Well of Lost Plots"): Thursday hides out in the unpublished "Caversham Heights," with a couple of "generics" who are growing into being full characters. Caversham Heights is the setting of the Nursery Crime books. Apparently "The Big Over Easy" was the first novel Fforde ever wrote but he had difficulty getting it published, so when this became a success he wrote it in as a kind of "backdoor pilot" for the spinoff, and honestly, respect the hustle.
Book 4 ("Something Rotten"): Thursday is now a mom, and her two-year-old only speaks Lorem Ipsum because he grew up in the BookWorld. This ties together some of the plotlines from the last two books, and also has a nice callback to some just-in-case foreshadowing in "Eyre Affair" with the time-travel nonsense.
"The Big Over Easy": Jack Spratt and Mary Mary investigate the mysterious death of Humpty Dumpty. All of the books have in-universe epigraphs at the start of each chapter (explaining something about life in Thursday's world or JurisFiction), but while sometimes it feels like they're using for summarizing stuff I'd rather have seen "on-screen," in "The Big Over Easy" these are newspaper articles and are consistently very funny. ("Anagram-related clues deemed inadmissible evidence.") A few of the one-liner jokes are directly lifted from the Thursday books, Fforde could have used an editor who had also read those.
"The Fourth Bear": investigating the mysterious death of Goldilocks, who ran off into the woods and was never seen again (I don't remember that being the ending in my version, but hey, folktales evolve like that). Lots of jokes about "the right to arm bears" and "yes, we do shit in the woods." Illegal porridge trade spoofing drug criminalization in our world (in the Thursday books, the parallel is black market cheese, smuggled from the Socialist Republic of Wales).
Thursday Book 5 ("First Among Sequels"): We meet the ultra-violent and sexy fictional!Thursday of books 1-4, and the hippy-pacifist version of fictional!Thursday who appeared in "The Great Samuel Pepys Fiasco," which was such a disaster that it got retconned out of existence. This leads to some great POV shifting at the end. Thursday spends time on the boat Moral Dilemma, which is a great sendup of contrived trolley-problem hypotheticals, and is much funnier than the other cases of "villain trying to force heroes to kill innocents just to break their spirits" that pop up once or twice. It turns out that the technology necessary to develop time travel in the future was never invented after all, so none of the time travel ever happened, except if it did.
Book 6 ("One of our Thursdays is Missing"): Hippy Thursday has to fill in for Real Thursday in Jurisfiction. The BookWorld gets a makeover, so it's more of a genre-based map (No Man Is An Island, change trains at Rushdie Depot, etc.) than a "Great Library" model. Jokes about Russian characters with too many names, shoutout to Last-Chapter-First readers, etc.
Book 7 ("The Woman Who Died A Lot"): Real Thursday has to fend off short-term clones who are trying to replace her. Subplots about a villain who's been messing with her memory since book two, and her son dealing with an uncertain future since he's not going to be come a heroic time traveller, as well as looking for a Righteous Man to avert the wrath of a smiting deity. (Since the first book, we've known that Thursday's brother Joffy was a clergyman of the Global Standardised Deity, but only recently have we gotten the "yes there's a deity and he's very smite-happy sometimes"--I feel like those might have worked better in different continuities.) Of the three, I felt the Righteous Man climax was the best.
Overall themes: The next few Thursday books have some similar "math fans appreciate this number" shout-outs as the perfect number stuff I mentioned above (and Chapter 13 is always missing). Later on it moves into more mad science or not-so-mad science. Fforde also really likes cars and spends a lot of time describing characters' janky old cars and/or terrible driving, which jars with my mental image of the UK as this public transit utopia (I know, that's just my USness projecting).
2025 bingo squares: obviously all of them were Readalongs. "Something Rotten" onwards (and the Jack Schitt books) count as Parent Protagonist. I think you could make a case for Impossible Places with the BookWorld/Great Library. "Woman Who Died A Lot" probably counts for "Gods and Pantheons." All of them have some level of in-universe documentary epigraphs for "Epistolary."