Whatever the final opening tally, the international box office haul for “The Avengers” already figures to be huge — inspiring audiences to assemble more in “Hulk Smash” than “puny human” numbers.If this Hulk-hued bounty looks like a slam dunk in hindsight, such brawny returns by no means were a given when Marvel Studios embarked on this mission — representing one of the most ambitious gambles in movie history, involving an interlocking five-movie, billion-dollar investment in a genre that historically has been a hit-miss proposition. Indeed, one gigantic misstep — hardly a far-fetched proposition given what Disney just experienced with “John Carter” — could have risked significantly shaking, if not outright toppling, the whole house of cards. In that context, what Marvel has accomplished — in concert with distributor Paramount and now as part of parent company Disney — marks the culmination of what can only be called a truly heroic case of chutzpah, or the audacity of HOPE (in this case, Hyped Openings Paralleling Expectations). The surprise success of “Iron Man” paved the way for this undertaking, signaling second-tier superheroes — those less known than Superman, Batman or Spider-Man — had untapped potential. Yet even with that, bringing the plan to fruition still required a remarkable balancing act, where many things had to go right to get from there to here. Nor did it bode particularly well when the second leg, “Iron Man 2,” turned out to be creatively flawed — easily the worst of the five Marvel titles. That includes “Avengers,” which, as satisfyingly constructed by writer-director Joss Whedon, is as much a collection of sly, humorous and occasionally rousing moments as a fully realized story, but as massive summer escapism goes, extremely good fun nonetheless. In between came “Thor” and “Captain America: The First Avenger,” which weren’t perfect but also proved entertaining and perfectly serviceable — faithfully adhering to the source material without causing the uninitiated to laugh in the wrong places. Although digital effects made much of this possible, tone is equally important — treating the characters seriously, in a way that appeals to the wary-yet-reliable Comic-Con crowd while still inviting in novices. Combining fidelity with the perceived need to “open up” these stories has always been tricky, and even “Avengers” contains interludes sure to produce shudders of joy in comicbook aficionados but destined to leave those unfamiliar with Marvel lore scratching their heads. Nevertheless, Marvel’s longterm strategy has created not just a single franchise, but — much like what those Stan Lee-Jack Kirby comics conjured in the 1960s — an integrated, teeming universe where fantastic characters coexist. This is all the more impressive given how many primary players in Marvel’s stable were parceled out to other studios during the company’s mismanaged, ignominious past. The crown jewel, Spider-Man, provided a windfall for Sony; X-Men and the Fantastic Four wound up somewhat circuitously with Fox; and the Hulk, arguably the second most-marketable property, rampaged through a pair of disappointments released via Universal. As things currently stand, Marvel/Disney find themselves light years ahead of principal rival D.C./Warner Bros., which seemingly possessed bigger marquee properties. Except as meticulously crafted by Christopher Nolan, Batman is rooted in its own dark reality, while Superman attempts a second reboot and “Green Lantern” — its first “Iron Man”-like foray — laid an emerald egg. Taking these factors into account, Marvel’s gambit has reinforced Disney’s move to acquire the company for $4 billion in 2009 and should quiet naysayers, much like the Pixar acquisition — which some financial analysts foolishly second-guessed, failing to recognize the vital infusion of creativity the animation powerhouse brought the studio. The benefits, moreover, will potentially extend outside movies to key ancillary areas — from the boy-oriented Disney XD channel, already immersed in Marvel tie-ins, to a merchandising footprint well beyond little girls and princesses. (Full disclosure: My wife works for a division of Disney.) Of course, the challenge now is to prove this wasn’t a fluke — the product of some radioactive run of good fortune — and do it all over again, unleashing spinoffs and sequels. None of those efforts are assured victory either, but like a costumed hero — even one who just saved the world — a movie studio’s job is never done, and tends to be judged by what you’ve done for us lately.