A decade in the making, Quentin Tarantino's World War II fantasy "Inglourious Basterds" conclusively answers questions that have hounded the filmmaker in recent years.

Does Tarantino still have the revolutionary directorial voice he displayed in his debut, "Reservoir Dogs"? Is he still capable of presenting a familiar genre from a startingly fresh perspective, a knack he had demonstrated with the game-changing, non-linear crime drama "Pulp Fiction"? Were the depth and maturity he had shown in his restrained, character-driven Elmore Leonard adaptation "Jackie Brown" just a one-shot deal, overridden by his passion for trash cinema?

The answers are yes, yes and maybe — but if he keeps making movies as good as "Basterds," then who cares?

The critical grumblings around Tarantino began with the two-part magnum opus "Kill Bill," in which he seemed to compress every chopsocky flick and revenge B-picture he had ever seen into one gigantic sprawl.

The complaints got louder with "Death Proof," Tarantino's contribution to a three-hour double feature titled "Grindhouse" in which he and director Robert Rodriguez paid homage to the tawdry 1970s exploitation movies that had influenced their craft.

But neither the public nor critics shared the filmmakers' enthusiasm. "Grindhouse" bombed when it was released in April 2007, a lackluster follow-up to the profitable but coolly received "Kill Bill Vol. 2." Suspicions arose that Tarantino had gotten lost in the junk-movie obsessions of his youth and was no longer relevant to the ordinary filmgoer.

The skepticism continues. Even though "Inglourious Basterds" received an 11-minute standing ovation at the Cannes Film Festival and earned Christoph Waltz the best actor prize for his portrayal of Nazi Col. Hans Landa, a self-proclaimed "Jew hunter," critical reaction to the film was mixed, the most extreme complainers branding it "an armor-plated turkey" and "a misfire."

The naysayers were wrong. Long, talky and utterly engrossing from the first scene, "Inglourious Basterds" is thrilling, invigorating filmmaking. This is Tarantino's best movie since "Jackie Brown" and a return to form for a director whose contemporary, big-city sensibilities had never hinted at a knack for a period war picture.

The combination sounds odd on paper but works like gangbusters on the screen.

"When I sat down to write 'Reservoir Dogs,' I just wanted to do a heist movie," Tarantino says from Los Angeles. "Here it was, 'I'd like to do a movie about a bunch of guys on a mission, but it has to be 'really cool.' I'm counting on the fact that I'll be working in this specific genre and that I will expand it and blow it up to some degree, while still offering the pleasures of that genre. So it was never about 'Let's do a World War II movie Quentin's way.' It's more 'Let's do a guys-on-a-mission movie,' and the Quentin part will happen on its own."

Unlike the fun but self-indulgent "Death Proof," which at times felt like a movie primarily designed for its creator to enjoy, Tarantino approached "Basterds" with the zeal of a first timer.

"On 'Death Proof,' it was like a party: We had fun, and we all goofed off, and the movie didn't work as well as his other films," says "Hostel" director Eli Roth, a friend and collaborator who acted in "Death Proof" and plays one of the "Basterds," a group of Jewish-American soldiers assigned by their commanding officer (Brad Pitt) to bring back the scalps of 100 dead Nazis.

"By comparison, 'Basterds' was like a military operation," Roth says. "Quentin was like a general on the set. He was very serious and very focused. He was on the set full time. He didn't even have a trailer. There were no cell phones on the set, no chairs, no monitors. We were there to make a movie, 'for' the love of movies, and the fun came in getting our shots right."

Aside from the Basterds' exploits and Landa's heinous crimes, the complex screenplay also interweaves the story of Shoshanna (Melanie Laurent), a French-Jewish theater owner in Paris eager to avenge the slaughter of her family, and a German actress (Diane Kruger) helping the Americans' cause.

Tarantino insisted that all the actors be of the same nationality as their characters, and more than half of the dialogue is in French and German, with English subtitles.

"Quentin doesn't speak French or German, but that doesn't mean he can't direct actors who are speaking it," says the Austrian-born Waltz. "He has this immense ability to pick things up. He would give me direction, and I would stand there with my mouth open sometimes, asking him 'How did you know that?' It didn't bother him that the words being used weren't familiar, because he's concerned with what is happening 'behind' the words."