A rollicking adventure through worlds both bleak and fantastic, Steven Spielberg's Ready Player One makes big changes to the specifics and structure of Ernest Cline's best-selling novel but keeps the spirit and level-up thrills intact. With Cline as a screenwriter alongside Zak Penn, it's not surprising that while some of the book's dorkier elements are excised — sorry, Rush fans! — their replacements display similar pop-culture obsessiveness while lending themselves more to the cinematic gifts of the man Cline surely dreamed would adapt the book. Gamers are far from the only ones who will respond to this virtual-world-set picture, which strikes an ideal balance between live action and CGI. The setting is 2045, in the fastest-growing city in the world: Columbus, Ohio. Around the globe, people spend as much of their free time as possible in an online virtual universe called the OASIS, where the focus is as much on living in a fantasy character's skin as on shooting things and keeping score. You can look like Beetlejuice and drive a Batmobile (1960s vintage, please); you can dance in zero gravity with a green-skinned swimsuit model; you can do anything to forget that, beyond your VR goggles, your physical body lives in a slum made of RV trailers stacked perilously high atop each other. The tech-artistic genius who created the place, James Halliday (Mark Rylance), died not long ago, and left OASIS members with one last game: Whoever can solve a series of clues and missions within the online world will inherit both his vast fortune and total control over what happens in the OASIS.

While mighty corporate interests — like IOI, a proletariat-exploiting company run by Ben Mendelsohn's Nolan Sorrento — are hiring teams of gamers to find Halliday's "Easter egg," hardcore geeks (the egg hunters, or "gunters") have the advantage, since the clues draw on every comic book, movie and video game the inventor consumed in his life — not to mention the biographical trivia housed in a vast archive of digitally reassembled memories. (That archive was just a published memoir in the novel; here, it's an entrancing living museum overseen by a stuffy butler-like robot.) Wade Watts (Tye Sheridan), known as Parzival in the OASIS, has been hunting for clues alongside his best friend Aech, a mechanical genius whose avatar is a giant black man with robot parts in his midsection. (The spoiler-averse should avoid looking at the credits to see whose voice is delivering Aech's lines.) From afar, the two have been admiring the egg-hunting work of Art3mis (Olivia Cooke), an anime-styled woman whose online motorcycle has Tron flair, and their paths cross in the movie's first really thrilling set piece: Gamers trying to solve the first challenge must win a car race whose course is a fast-mutating obstacle course, where wrecking balls or a T-Rex will kill you if the road doesn't simply uproot itself under your wheels and throw you off. The obstacle just before the finish line is a doozy, but the trick to beating the thing is even more fun. Soon, Parzival beats the first challenge, followed by Aech, Art3mis and a pair of Japanese players, Daito (Win Morisaki) and Shoto (Philip Zhao). Uniting these five as a team more quickly than the book did, the film lays the groundwork for a big change that is key to its success as a film: Midway through, it starts bringing them together in the real world, getting them in trouble that gives the action both flesh-and-blood stakes and offers viewers a break from the well-executed but fake-by-design character avatars. Parzival's crush on Art3mis is vastly more interesting when we watch Sheridan and Cooke share the screen together, and returning to the world of slums and class warfare helps imbue the battle between gunters and IOI the flavor of a rebellion. Though the workings of the megacorp's debt-enslavement scheme aren't fleshed out much, it's clear that if they gain control over the OASIS, the kind of garbage we face on our own internet and social media will enjoy next-generation proliferation there.

Mendelsohn does his usual mustache twirling as Sorrento sends both real-world hit squads and a virtual bounty hunter after our heroes. The latter, a cartoonishly menacing hulk voiced by T.J. Miller, gets most of the film's laughs. (The lines sound written specifically for, or by, the former Silicon Valley actor.) Rylance gets to play a few versions of the OASIS's eccentric inventor, and seems most to enjoy being the space-cadet genius, his jaw slackened and his delivery stoned-sounding. (It costs a hundred dollars-plus to see this wonderful actor create a character on Broadway; please, Hollywood, keep giving us access to him for the price of a movie ticket.) The movie's biggest attractions can't be described here without ruining the fun of mystery-solving and spoiling surprise appearances of characters we treasure from our own childhoods. The trailers reveal the very welcome presence of the Iron Giant, whose role in the climax is sweetly true to the character's nature. But other guest stars play significant roles in the action as well, and they're not necessarily the ones fans of the novel will expect.