With “The Post” Steven Spielberg proved that he can still make a first-rate serious film, but of late when he’s taken on something involving special effects, he goes overboard. “The BFG” had moments that recalled the sense of wonder the director used to be able to achieve with relatively modest means in a picture like “E.T.,” but it faltered under the weight of all the CGI he poured over the story like a heavy sauce.

Now Spielberg offers an adaptation of Ernest Cline’s 2011 novel that represents major overkill in that department. Confusing exhaustion with exhilaration, after awhile “Ready Player One” becomes more an assault on the senses than a pleasant diversion. And when at the close it offers the moral that one should learn to appreciate reality rather than the “alternate” virtual reality in which the movie has immersed you for more than two hours, you might be tempted to wonder whether you might have better spent that time walking in the park or talking, face-to-face, with a friend than watching it.

Spielberg has dealt with science fiction after a fashion before, of course, not just with “E.T.” and “Close Encounters” but especially in “AI: Artificial Intelligence.” In that instance he took a cerebral approach, pretty much mandated by the fact that he was working from a treatment fashioned by Stanley Kubrick, who showcased effects that were groundbreaking at the time in “2001” but used them to create a mythic, thought-provoking world of its own. By contrast “Player” is just a riot of sight and sound that’s also a nostalgia trip of humongous proportions—a cinematic roller-coaster ride that goes on so long you want to shout for it to stop and let you off, already.

The movie also suffers, as so many video-game pictures have, from the fact that it can’t truly replicate, in a straightforwardly narrative way, the interactive experience of the games themselves. Obviously there’s no chance for the viewer to determine what’s going to happen next; he must simply accept the trajectory that Spielberg, his scripters Cline and Zak Penn, and their effects colleagues have cooked up for him. He’s effectively watching the game they’re playing, and they’ve also made up the (largely incomprehensible) rules for it. Still, for some that vicarious thrill ride will be enough.

The story, set in the Columbus, Ohio of 2045—the fastest-growing city in the world, we’re told in extensive opening narration, by reason of the fact that it’s the headquarters of the company that birthed Oasis, an online virtual reality game that has become an obsession with most of the population, offering them respite from their miserable depressing lives by allowing them to live adventurously, and amass coin, through the self-chosen avatars they inhabit in the virtual world.

The narration is spoken by the eighteen-year old hero, Wade Watts (Tye Sheridan), an orphan living in a fifth-story trailer with his aunt (Susan Lynch) and her latest brutish boyfriend (Ralph Ineson) in The Stacks, a wretched ghetto in this dystopian future. He escapes his unhappy home life by donning the visors that take him into Oasis, where he hangs out as Parzival, his blonde, leather-clad avatar, often in the company of his best pal, Aech (Lena Waithe), who takes the form of a big greenish ogre with some metal appendages.

Their main preoccupation is trying to win a contest announced by James Halliday (Mark Rylance, who seems to be having fun playing the character as utterly distracted at all stages of his life) via a posthumous message. He inserted a special “Easter Egg” in Oasis when it was created. The first gamer to find it will win all Halliday’s shares in the company, worth an immense fortune. But to get to the egg, the gunters, as they’re called, must win a series of three contests, each of which ends with the victor receiving a key from Halliday’s avatar that will unlock a clue that must then be deciphered to take one to the next level. And being able to do that requires as thorough a knowledge as one can muster about Halliday—which explains why some players visit the archive of the master’s memories to see the events of his life replayed like clips from a movie.

Parzival becomes a hero by winning the first challenge—a race in which he meets beautiful Art3mis (Olivia Cooke), who eventually joins him, Aech, and their two other comrades Daito (Win Morisaki) and Shoto (Philip Zhao), in going after the remaining keys. But there is a villain scheming to take the prize for himself: Nolan Sorrento (Ben Mendelsohn), head of the rival Innovative Online Industries (or I.O.I.), who aims at taking over the entire virtual-reality business and will stop at nothing to achieve his aim. He has an avatar in Oasis too, but more important a right-hand man there, Skeletor-like i-Rok (T.J. Miller), who will acquire the magical artifacts Sorrento needs to strengthen his chances of winning in case his army of nerds and soldiers back at corporate headquarters prove not to be up to the task.

“Ready Player One” includes so many pop culture references—to movies and songs as well as video games—that it will probably give rise to catalogues of them compiled by fanatical geeks everywhere. But such a labor of love would require multiple viewings of the movie, which—with its eye-popping visuals, shot by in blazing images by Janusz Kaminski and edited hyper-kinetically by Michael Kahn, and bombastic sound, the combined result of the effects team and composer Alan Silvestri—would probably result in the seizures some Japanese videos were once reported to have caused in their viewers.

That’s not to say that the picture isn’t technically impressive; it is. But it contains entirely too much pizzazz, and the last confrontation—or series of confrontations, actually—threaten never to end. The law of diminishing returns is definitely operative here.

Not surprisingly, the movie is at its best in the scenes in the second half where the gamers leave their avatars behind and connect as actual human beings. That section basically turns into a chase, interrupted by scenes of a massive virtual battle going on for control of the Easter Egg—a fight to which Wade/Parzival has summoned all his fellow gamers for help against Sorrento’s minions—but it’s nice to see real actors involved, even if their characters are paper-thin. Sheridan makes a pleasant hero, if a somewhat colorless one; Cooke, who in her human form frets over a Gorbachev-sized birthmark, is spunky; Waithe brings plenty of attitude to the human Aech; and Morisaki and Zhao provides a bit of comic relief.

Unfortunately, Mendelsohn, who has brought some real menace to earlier roles, proves a thoroughly feeble villain. One’s thankful that he’s accompanied in many scenes by Miller, who might never appear out of his avatar getup, but has some amusing lines of dialogue in it. And Rylance provides some dry humor, as does Simon Pegg as his erstwhile partner.

There is one sequence in “Player” worthy of particular mention—the one in which the second key is revealed. It constitutes a homage to Kubrick, in this case to “The Shining,” and includes a marvelous recreation of the Overlook hotel and of several moments that occur within it in the original film, though they’re now inhabited by our heroes’ avatars. Though the sequence goes haywire in its later stages, which become frenzied and effects-laden, for the most part it’s delicious, especially for film buffs, in its attention to Kubrick’s creepy vision. It’s no surprise that until it careens off the rails, this segment is a uniquely quiet episode within the Oasis, which helps to explain why it’s so effective in comparison to the chaos going on around it.

There’s another episode in the movie that’s telling. It occurs when Sorrento tries to seduce Wade into joining forces with him, offering him plenty of money to do so. As part of his spiel, the mogul uses a stream of pop culture tidbits referencing such items as the name of the high school in John Hughes’ “Breakfast Club” and “Ferris Bueller’s Day Off.” Naturally the clueless guy is being fed the information via an earpiece by one of his resident nerds. In a way “Ready Player One” seems to emulate that scene—it’s as though Spielberg were trying to show how cool he still is by making a movie that’s an avalanche of such tidbits, delivered so rapidly that the accumulation is overwhelming.

That’s not to suggest that the director is like Sorrento in being clueless about the references (most are from the seventies and eighties, after all—the era that also provided the material for “The Post”). Rather it suggests that he too is making use of them to prove his relevance in today’s fantasy genre, when some have suggested that his place has been taken over by younger filmmakers more in tune with contemporary culture. If so, he’s gone overboard in the attempt.