Fair for Its Day: The Last Woman In His Life in its treatment of homosexuality. It doesn't seem like the authors understand same sex attraction, equating it with parent-induced gender dysphoria. On the other hand they don't seem to see it as a bad thing either, and the Sympathetic Murderer makes a good point about the way homophobia played into the crime.
Television Series
Ass Pull: The Dying Clue in the Pilot Movie actually makes no sense, given how the victim supposedly wanted to draw the police’s attention to what was playing on a TV set even though that clue only appeared almost the exact second she died and she spent several seconds before that trying to set up the clue, while something completely different was on TV.
Base-Breaking Character: Girl of the Week's Jenny O'Brien and Lorelei Farnsworth. Some fans like them for having somewhat active roles in the mystery and being among the more developed female characters. Others find them annoying with their presence throughout the investigation a bit forced. Lorelei Farnsworth, for instance, throughout the entire episode hounds Ellery to help her with the romance novel she is writing despite Ellery repeatedly telling her that he does not write romance novels.
Canon Foreigners Simon Brimmer, the snobbish radio sleuth, and (to a lesser extent than Simon) Intrepid Reporter Frank Flannigan make a strong impact on the franchise with their appearances in this series.
Gail Stevens from the pilot is a particularly popular suspect given her dynamics with the McKell family (some of her fellow suspects) and Ellery as she offers help throughout the case.
Margie Coopersmith and Kitty McBride are probably the best-liked of Ellery's various love interests (although it's debatable if Margie is a love interest or just a colleague). Margie's popularity comes from being decently quirky and helpful while coping better than most with Ellery's own quirks (and her presence feeling more justified than the Base-Breaking Character's mentioned above), and Kitty is well-like for telling off Ellery for his absent-mindedly missing a date on New Year's Eve in an understandably irate fashion but showing a somewhat warmer side at the end of the episode.
Moe: Margie Coopersmith from "The Adventure of the Pharoah's Curse" is a polite, constantly smiling secretarial temp, who makes a lot of endearing but useful Fangirl comments about both the manuscript she's helping Ellery with and the mystery. She is a pleasure to watch through it all.
Nightmare Fuel: the opening of "The Adventure of Lover's Leap". The Victim of the Week is reading the titular book by Ellery, and the opening paragraphs, obviously meant to evoke an atmosphere of dread, perfectly match what's happening to the woman reading. At first it predicts what's happening around her (a dog howls, a car pulls up), then reiterates what's just happened (she goes to the balcony to look down at the driveway, only to find no car there). It's low-key, but very creepy; it wouldn't be out of place in an episode of The Twilight Zone.
Referenced by...: Lupin III: Part 6 had homages and cameos by various fictional detectives, including "Inspector Queen" of the New York City Police Department.
Some of Ellery’s love interests were interesting enough and fans wish they could have had one reappear in the place of the less popular ones.
Ramon from the pilot has little to no dialogue and is killed off in a contrived fashion despite an interesting chase sequence and his potential for a good speech when it turns out that he was sleeping with his boss's mistress and was Wrongfully Accused of her murder.
It would have been something to have both Jerk with a Heart of Gold rival detectives, snobbish Attention Whore Simon Brimmer and crass yellow journalist Frank Flannigan (who would have made perfect Foils to each other) appear in the same episode and either compete with each other as well as Ellery or try to team up to get to the solution first.
The standard "Simon accuses the wrong person" set-up could have been neatly twisted, while still remaining true to the spirit of the character, if for once he'd gotten the right person but just the wrong evidence (either something that he was mistaken about or that couldn't be concretely proven), while Ellery still solved the case.
The pilot movie has a Sequel Hook about Ellery going to investigate the murder of an art collector whose paintings were all turned to face against the wall, but this is never shown or referenced in the series.
Too Good to Last: The show is an Acclaimed period piece with good chemistry between the cast and some clever mysteries, which nonetheless lasted just a single season due to the large number of detective shows competing with it, and some say the star's poor health. The only consolation comes from the fact that its short run helped inspire the creative team to launch Murder, She Wrote eight years later.
Values Dissonance: Unsure whether it's Truth in Television for 1947 (when the series is set), but in 2020 it's quite uncomfortable to notice that most of the few characters of color (whether black, Asian or Latino) are menial servants of some kind, including in the background at formal events. The few exceptions are the black couple in "Sunday Punch"—one of whom is studying to become a pharmacist—, the Egyptian Professor in "Pharaoh's Curse", and the Chinese WWII veteran and artist in "Judas Tree", who travels around in a limousine. There's also Doyle in "Tea Party", where the black butler turns out to be a Pinkerton detective undercover. "Tyrant of Tin Pan Alley" also features a black man working in a diner (YMMV again whether that's menial or not).
