Image copyright Warner Bros Image caption Tye Sheridan plays Wade Watts, the film's teenage hero

Steven Spielberg's Ready Player One has dazzled critics at the South by South West (SXSW) festival, with one calling the film "a mesmerising blockbuster".

The director's "biggest crowdpleaser in years", says IndieWire's Eric Kohn, is both "an astonishing sci-fi spectacle and a relentless nostalgia trip".

Set in the year 2045, the film unfolds in a dystopian world whose inhabitants take refuge in a virtual reality game.

The result, says Forbes' Charlie Fink, is "an instant sci-fi masterpiece".

Image copyright Getty Images Image caption Steven Spielberg introduced the screening on Sunday night

Ready Player One, released in the UK on 28 March, was premiered on Sunday at the Paramount Theatre in Austin, Texas.

The SXSW preview was hit by sound problems that led to it being briefly paused - prompting, joked Spielberg afterwards, "probably the greatest anxiety attack I've ever had".

The technical difficulties did not stop members of the audience raving about the film, among them fellow director Robert Rodriguez.

The Spy Kids film-maker described it on Twitter as "classic Spielberg fun" that would "reward repeat viewings".

Skip Twitter post by @Rodriguez #ReadyPlayerOne is classic Spielberg fun! What a blast, can't wait to see it again. Rewards repeat viewings. Tons of great references, visuals and heart. So kick ass it blew the speakers! — Robert Rodriguez (@Rodriguez) March 12, 2018 Report

Based on a 2011 novel by Ernest Cline, Ready Player One sees a group of teenagers embark on a quest inside a simulated reality known as the Oasis.

The film features a plethora of references to '80s pop culture, among them Batman, the Iron Giant and the DeLorean from Back to the Future.

Nods to King Kong, The Shining and Spielberg's own Jurassic Park also figure in a film Variety describes as a "dizzyingly propulsive virtual-reality fanboy geek-out".

Image copyright Warner Bros Image caption The time-travelling DeLorean from Back to the Future makes a cameo appearance

The Hollywood Reporter, meanwhile, calls it "a rollicking adventure through worlds both bleak and fantastic" that "strikes an ideal balance between live action and CGI".

Ready Player One follows hot on the heels of Spielberg's drama The Post, which was released in the UK in January and was nominated for two Oscars.

Part of the film was shot in Birmingham's Jewellery Quarter, which doubles for the film's futuristic vision of Columbus, Ohio.

The South by South West Festival continues until 18 March.

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