While he was alive, critics had little trouble finding ways to discount Alfred Hitchcock’s genius and underrate his later decades of entertaining, bubbly and even chilling thrillers. Because that generation of reviewers remembered “The 39 Steps.”

This 1935 romp of a thriller followed the 1934 version of Hitchcock’s “The Man Who Knew Too Much.” Yes, he’d remake that espionage thriller during his glorious peak decade, the 1950s. But he’d remake “The 39 Steps” many times and in many ways, often repeating the “public spectacle” trick he’d tried out in the 1934 “Man Who Knew Too Much” (the “cantata scene”) in many films, including his 1959 “Hitch’s Greatest Hits” thriller “North by Northwest.”

“The 39 Steps” bounces through English music halls and onto Scottish moors with an accused murderer on the run to clear his name and foil those smuggling the film’s “MacGuffin,” state secrets of a military aviation nature.

It’s sexy, silly and suspenseful, a colorful delight filmed in sharp, crisp black and white.

Robert Donat served as the prototype for the sort of Hitchockian hero that a lot of actors would play, most famously Cary Grant — playful and imperiled, flirty and when the moment called for it, flinty in ways we could never foresee.

The future Oscar winner (“Goodbye, Mr. Chips”) Donat would have an illness-impaired career that included more stage successes than screen ones, and more’s the pity, based on the dash and droll wit he brought to Hannay, a Canadian caught up in between-the-world wars British intrigues.

Hitchcock & Co. preserved a grand taste of “English Music Hall” with rambunctious, amusingly unruly scenes of show folk doing their acts as the sometimes tipsy punters howl their approval or disapproval from “the stalls” and the cheap seats.

That’s where the Canadian Hannay glimpses the rough treatment of some acts — including the “Mr. Memory” act — an evening of entertainment interrupted by gunshots.

In the middle of the not-quite-riot that ensues, he’s buttonholed by a mysterious and quite paranoid foreign beauty (Lucie Mannheim).

“May I come home with you?” Nudge nudge, wink wink “Say no MORE” is implied, with “It’s your funeral” the part Hannay says out loud.

Once there, Hannay gets “Annabell” to reveal her name, and realizes she’s not delusional. She really IS being followed. And she really was the one who “fired the shots” that disrupted the show to make her escape.

She speaks of “The 39 Steps,” of a remote village in Scotland, of government secrets that have been stolen and of contact with a man missing the top joint of his pinky finger. Hannay awakens to her final gasps, a knife stuck in her back.

He knows how this looks and makes his escape — by milk wagon, by rail, with newspapers ensuring that the whole of Britain is onto him. It’ll take his most convincing arguments and all his charm to find “the real killers” and unravel a very real “plot.”

Madeleine Carroll plays the Hitchcock Blonde Hannay stumbles into who is VERY relunctantly enlisted in his getaway/get the bad guys scheme. She doesn’t believe a word of his “story.”

“Has that penetrated?”

“Right to the funny bone. Now tell me another one.”

Being manacled to a possibly murderous mustachio’d rake who passes you off as his “wife” at a Scottish inn isn’t any lady’s idea of a tea party. Not everything here points to the plot being something of a lark. But an awful lot of it does, and amusingly.

Hannay shares a rail car with a woman’s undergarments salesman and his chatty/saucy friend. The innkeeper (John Laurie) may not know or much care if Pamela (Carroll) and her gent are “married.” But his wife (the future “Dame” Peggy Ashcroft) is damned if she’s letting trench-coated goons or anybody else stand in the way of true love.

The story’s clockwork problem-solving was a template for many a Hitchcock thriller to follow. Striking location shooting blends nicely with soundstage bridges, moors and the like in Oscar Friedrich Werndorff’s production design, flawlessly filmed by director of photography Bernard Knowles and his crew.

Hitchcock’s deep appreciation for “montage” (editing) in cinematic storytelling had formed in his silent cinema years and achieved the early polish of perfection in “Steps” editor Derek N. Twist’s skilled manipulation of chases, narrow escapes and immersing the viewer in the now-long-dead music hall experience.

Carroll wasn’t Hitchcock’s first blonde siren, and was far from his last. He’d replace Donat with Cary Grant and James Stewart in later years — serious leading men with a light touch.

The urbane, pinky-maimed “professor” villain here (Godfrey Tearle) and his remote Scottish mansion are but rough drafts for James Mason, Leo G. Carroll and the Mount Rushmore cliffside home of “North by Northwest.”

Later villains would never confuse their semiautomatic pistol for a “revolver” when pointing it at our leading man.

But “The 39 Steps” is so effortlessly, self-consciously clever that even non-Hitchcock fans should be won over by its playful sense of adventure and suspense and the timeless wit and sexual edge on display.

“There are 20 million women on this island and I’ve got to be chained to you!”

Generations of critics and film scholars would joke that one learned to never “fear” for a jaunty Hitchcockian hero, or even a “Hitchcock blonde” until “Psycho” upended those expectations. But the urtexts for Hitchcock plotting, Hitchcock suspense and the jokey Hitchcock style are still preserved for new fans to appreciate here.

If you don’t get a kick out of “The Man Who Knew Too Much” or “The 39 Steps,” that’s the best reason to see watch them again. It’s high time you realize what you’ve been missing.

Rating: approved, violence

Cast: Robert Donat, Madeleine Carroll, Lucie Mannheim, Peggy Ashcroft and Godfrey Tearle

Credits: Directed by Alfred Hitchcock, scripted by Charles Bennett and Ian Hay, based on a novel by John Buchan. British Gaumont release on Tubi.

Running time 1:26