Iron Man 3 is the summer’s biggest box office hit… and miss. Strap in for two hours of Pepper Potts kicking more ass than Tony Stark.

If a mosquito bit Steven Spielberg around the time he was making “Jurassic Park,” then became trapped in amber until some nut with more money than forethought extracted the DNA from it and cloned an early ’90s version of Spielberg, well, that’s the guy I could see directing “Ready Player One.”

But for the actual Spielberg, now 71, to be able to tap into his boy-genius mojo after the likes of “Schindler’s List,” “Amistad” and “Munich” to deliver such a rousing technical achievement while incorporating the broken families and outsiders of some of his best-loved works is nothing short of phenomenal.

Based on the novel by Ernest Cline, who co-wrote the script with Zak Penn (“The Incredible Hulk”), “Ready Player One” is centered around young Wade Watts (Tye Sheridan, “X-Men: Apocalypse”). An orphan living with his aunt and her latest loser boyfriend in the Stacks, a series of mobile homes literally stacked like makeshift high-rises in Columbus, Ohio, Wade finds refuge in the virtual universe known as the OASIS.

It’s 2045, years after the corn syrup droughts and the bandwidth riots, and almost everyone, regardless of their income, practically lives inside the OASIS. And why wouldn’t they when they can do literally anything Spielberg and Warner Bros. could obtain the rights to, including climbing Mount Everest with Batman?

Inside the OASIS, Wade is known by his avatar Parzival. In real life, he’s never even met his best friend, whose avatar, Aech, is a massive, beastly mechanic. They’re mostly content to drive in street races for coins and a chance to unlock the first piece of the puzzle that the late OASIS designer James Halliday (Mark Rylance) left as a Willy Wonka-style inheritance. Whoever finds the three keys and the Easter egg hidden somewhere in the OASIS will control the virtual world as well as Halliday’s vast fortune.

It’s been five years since Halliday died, and no one has even cracked the first clue. Warner Bros. could sponsor a similar contest, asking moviegoers to spot all the pop-culture references in “Ready Player One” and it would prove nearly as difficult. (To give you a hint without ruining any of the surprises, the DeLorean from “Back to the Future” and the Iron Giant are on the movie’s poster.)

But after Parzival saves Art3mis (Olivia Cooke, “Bates Motel”), who resembles a sexy, anime porcupine, during a race, he starts to take the contest much more seriously. They’re determined to keep the OASIS in the hands of Gunters (egg hunters) like themselves and Aech and away from the Sixers, debtors who’ve been co-opted into hunting for the egg by Nolan Sorrento (Ben Mendelsohn, “Bloodline”), the nefarious head of Innovative Online Industries.

They’ll also have to survive the bounty hunter known as i-R0k, who shares the voice and, most hilariously, the attitude of T.J. Miller (“Silicon Valley”) and looks like Skeletor ate another Skeletor and then coughed up a RoboCop.

The virtual world of the OASIS looks nearly as magical on screen as it must to the millions of its goggled users. To emphasize the contrast, Spielberg created the OASIS scenes digitally using computer animation and motion-capture technology and shot the real-world moments on film. The effect is like bouncing back and forth between the Technicolor wonderland of Oz and the drab black-and-white Kansas.

“Ready Player One” goes on a bit too long, and several of the non-OASIS scenes tend to drag. Moviegoers who aren’t obsessed with video games or didn’t come of age with Buckaroo Banzai may be left scratching their heads during the onslaught of pop-culture references that come across in various avatars. Many of them stem from the late 1970s through the early 1990s, the era with which Halliday, whom Rylance portrays as Bill Gates by way of an aging Garth Algar from “Wayne’s World,” identifies.

It’s tough to tell whether the Gunters are obsessed with that era because they’re obsessed with Halliday, or if they’re simply immersing themselves in the nostalgia to give them an edge in the contest.

Regardless of their intent, “Ready Player One’s” massive battle scene with trademarks colliding like rarely before, has taken an early lead for biggest geek-out of the year. It’s like “The Lego Movie,” only with more heart — and more joyous thrills, depending on how well you know your movie, music and video game history.

Just like Halliday’s contest, “Ready Player One” is designed to reward the nerdiest among us.

Devastating images of the Halifax Explosion, a cataclysm so great that some victims were blinded simply by looking at it.

“Hold up the train. Ammunition ship afire in harbor making for Pier 6 and will explode.”

These were the last words of Vince Coleman, the train dispatcher who met his end on December 6, 1917, in the Halifax Explosion. Seconds later, the ship would explode and set off the 3,000 tons of explosives inside. It would be the biggest and most devastating explosion in history until the invention of the nuclear bomb.

The Halifax Explosion started when two ships collided in the harbor of the Nova Scotian capital of Halifax. A Norwegian ship, the SS Imo, had slammed into the SS Mont-Blanc, a French ship filled to the brim with TNT, picric acid, benezole, and guncotton.

The collision cracked open the barrel of benezole, dousing the ship in flammable chemicals. Then the SS Imo’s engine kicked in, setting off a spark that would kill thousands.

All 3,000 tons of explosives then went off at once, burning with a heat of more than 9,000 °F. In seconds, the flames eviscerated every building in a half-mile radius, while a brutal shockwave tore through the rest of the city, traveling more than half a mile per second and shaking the city to its bones.

The inferno tore through Halifax, burning so bright that some were blinded just from looking at the light of the explosion. Others were trapped inside their homes by the roaring fires around them. They had no way to escape from the smoke that slowly choked them and the flames that left nothing but ashes in their wake.

“The sight was awful,” one witness said. “People hanging out of windows dead. Some with their heads missing, and some thrown onto the overhead telegraph wires.”

By the end, the Halifax Explosion had ended 2,000 lives and seriously injured at least 9,000 more.

As horrible as it was, though, it would have been worse if it wasn’t for that one final message from Vince Coleman. He stayed at his post to make sure the train bound for the harbor wouldn’t come in. He gave up his chance for one last mad dash for survival to save the lives of the 300 people on board that train.

“Guess this will be my last message,” Coleman said as he watched the flames burn through the hull of the SS Mont-Blanc. “Good-bye boys.”