A stunning festival slate — including ''12 Years a Slave'' and ''Gravity'' — rings the opening bell on awards season

Toronto is not just a film festival. It’s a battleground. Each September, many of the year’s best movies head north for the annual screening series, which Hollywood regards as the official kickoff to the Oscar race. (For the record, Argo and Silver Linings Playbook were both hits here last year.) It’s no easy feat to emerge on top: In the era of Twitter reactions, buzz can give way to backlash in an instant.

Without question, the must-see movie at the festival this year (which opened Sept. 5 and runs through Sept. 15) was 12 Years a Slave, starring Chiwetel Ejiofor as a free black man who is kidnapped in 1841 and sold as a plantation slave. ”This movie was labeled the impossible movie, and the fact that we made it, and the reaction to it, just humbles me,” director Steve McQueen told EW, still looking a little shell-shocked. He wasn’t the only one. 12 Years a Slave (in theaters Oct. 18) had an emotionally crushing Toronto premiere on Sept. 6 that left many in attendance stunned as they left the theater, uttering only ”Oh my God” and ”Wow” instead of the usual chatty analysis. That came later, of course, with many festivalgoers predicting Best Picture, Actor, Director, and Adapted Screenplay honors, among others, for the film. Still, the race is far from over: Several veteran Academy members who hadn’t yet seen it said they were put off by reviews describing the film as ”brutal” and ”relentless.”

Alfonso Cuarón’s Gravity (Oct. 4) was the other major hit, with its startling visuals of Sandra Bullock and George Clooney as two astronauts stranded in orbit after a catastrophe destroys their shuttle. Bullock’s performance was so strong that numerous audience members at the post-screening Q&A asked her about Best Actress possibilities, which she tried to deflect: ”The beautiful thing about film festivals is you always have an amazing array of films to have that conversation about. This year seems to be extraordinary…. So that’s always going to be the talk.” It won’t be the last time she’s asked about her Oscar chances this year.

Jason Reitman’s Labor Day (Dec. 25), starring Kate Winslet as an unstable single mom who gives shelter to Josh Brolin’s escaped convict, roused passions, but the movie seemed to split audiences by gender: In general, women raved, while men shrugged off the drama’s romantic elements. Other films causing a stir included Ron Howard’s Rush (Sept. 27), about a true-life Formula One rivalry. Chris Hemsworth plays heartthrob driver James Hunt, but costar Daniel Brühl received all the Supporting Actor Oscar talk for his intense, abrasive performance as calculating racer Niki Lauda, who was horribly burned in a 1976 crash. (The real Lauda made an emotional appearance at the Sept. 8 premiere.) Meanwhile, the Hugh Jackman/Jake Gyllenhaal child-kidnapping thriller Prisoners (Sept. 20) had a remarkable ensemble, but it was Aaron Guzikowski’s gripping original screenplay that was vaulted into the Oscar race.

Among those that stumbled at the festival: Mandela: Long Walk to Freedom (Nov. 29) was knocked for condensing its story to a series of highlights from the life of the historic South African leader, although Idris Elba earned respect for his charismatic performance. A similar fate befell the WikiLeaks drama The Fifth Estate (Oct. 18), which opened the festival with raves for Benedict Cumberbatch’s portrayal of hacker-journalist Julian Assange. Sadly, its jumbled storytelling dampened the rest of the movie’s Oscar buzz.

One of the pleasures of the festival is seeing unexpected favorites emerge. Going in, anticipation focused on Matthew McConaughey’s extreme-weight-loss performance as a homophobe dying of AIDS in Dallas Buyers Club (Nov. 1). While that remained true, the surprise was an equal outpouring of acclaim for Jared Leto’s supporting turn as an ailing transgender woman. It’s Leto’s first role in four years, and his highest-profile one since Requiem for a Dream. ”I’ve gotten more effusive praise in the past 48 hours than for anything in my entire life, so I have a lot to be grateful for,” Leto told EW, before summing up the entire festival with a succinct two words: ”Pretty wild.”