Guys, we need to talk about “Thor: Ragnarok.”

If you aren’t onboard yet for the Marvel Cinematic Universe gravy train, this movie might not be for you. For those paying attention, "Thor: Ragnarok" brings an unexpected cavalcade of fun. Director Taika Waititi takes everything we know about Thor and flips it: Thor stops being so serious and delivers some truly funny lines, Loki stops the grand speeches and becomes even more cowardly while Hulk/Bruce Banner adds to the hilarity with his sulky baby routine. Add to that some of the funniest cameos in Marvel’s cinematic history and we’ve got one jokey Marvel jam that has a measure of joy missing from previous Thor films.

One caveat: all the fun seems to have sapped a sense of immediacy to the story – the plot is so weightless that it breezes by without changing much to the Marvel status quo. Then again, why worry about gravitas when you’ve got a shot of the Hulk beating up a 10-story fire demon in Asgard?

This is the third movie in the Thor series starring Chris Hemworth as Asgard’s favorite son with Tom Hiddleston as Thor’s brother, the shifty god of mischief Loki. At the start of the film, Thor finds out what we’ve known all along – that Asgard has been taken over by Loki after banishing their father, Odin, to Midgard in their last adventure together. Thor and Loki go on a search for Odin only to be attacked by Hela, the goddess of death, played with seductive relish by Cate Blanchett. A battle on the Bifrost leaves both Thor and Loki banished from Asgard and into the "junk planet" of Sakaar, a backwater that seems to function as the Marvel Universe Garbage Patch. Without a Bifrost, there is little hope that the two Asgardians can come home. Will the two brothers survive the gladiator ring of of the Grandmaster and set aside their differences long enough to work together and stop Ragnarok?

Plotwise, "Thor: Ragnarok" has none of the wonky asides expected of Waititi as seen in his movies such as "What We Do in the Shadows" and "Hunt for the Wilderpeople." Thor proves Loki's mischief, searches for Odin, fights Hela, ends up in Sakaar, fights Hulk, and brings it all home to Asgard for one final fight. You can practically fill in the blanks on what happens because the story hardly ever detours into unexpected territory -- like the farmhouse scene in "Avengers: Age of Ultron" or Starlord going back inside the Kyln to save his Sony Walkman.

What "Ragnarok" does pack in over its two-hour runtime is all sorts of Waititi/Heavy Metal weirdness. Hemsworth gets bonus points for his hilarious attempts to calm down Banner/Hulk while also unleashing the potential of his thunder god powers. The Hulk also gets his turn to shine as he takes on both Surtur and Fenrir, proving why he's the strongest Avenger.

Also in the running for Marvel's MVP is Tessa Thompson's Valkyrie, a boozy, battle-scarred warrior whose introduction shows her falling off a platform drunk before wiping out an army of bad guys. Valkyrie is going to be an interesting addition to the Marvel hero roster - a Wonder Woman without the invisible jet or the bracelets - because she can be funny while going toe-to-toe with the Avengers' big guns.

The Grandmaster, played by Jeff Goldblum, is also a blast as a needling, tricksy ruler who can be liberal with executions but is only out to seek entertainment in the gladiator ring.

Other bits of amazing "Ragnarok" weirdness: Frank Frazetta-like scenes of war between Thor and Hela's minions, Valkyrie taking on Hela; that hilarious battle between and Thor and Hulk, Odin going the Yoda route and the best use of a Led Zeppelin song in a movie.

So what's missing then? If "Thor: The Dark World" is accused of being too serious and missing out on the fun, this third movie seems to have swung the opposite direction. When everything is permeated with a sense of playfulness, of everything being a joke, an act of serious selflessness then gets added weight.

I was surprised how much I liked Heimdall, played by Idris Elba, in the movie. In his first outings, Heimdall was the stoic watchman of Asgard, activating the Bifrost and keeping a watch for enemies. Here, he acts more like Asgard's king than Thor - saving the citizens and fighting off Hela's army. Heimdall doesn't get a lot of lines but his actions make him even more heroic than Thor.

There are also story beats in "Thor: Ragnarok" that fail to pop: basically every scene with Hela in Asgard is a clunker and Skurge the Executioner is given an extended cameo just to bring one iconic Walt Simonson panel to life. Also a miss is mining the Greg Pak "Planet Hulk" storyline from the comics and doing nothing with it: why maroon the Hulk in Sakaar when he's only seen fighting one champion? Adding Korg and Miek to the action just makes you miss why they're such interesting characters.

Perhaps the biggest culprit then - that sense of lightweight fluff on "Ragnarok" - is serialized storytelling: we know the heroes will be fine because we have "Avengers: Infinity War" coming up. Even Thor's massive injury near the end seems to have been shrugged off because the story is moving too quickly, like someone at Marvel was checking off the boxes to get Thor and the gang to where they need to be for the next adventure. The stakes are too low; these are no longer self-contained, one and done adventures. The Marvel wheel will keep on spinning.

Is "Thor: Ragnarok" a good movie? Of course. Is it funny? Absolutely. Will it make a billion dollars in the box office? It's got a good shot at it, sure. Is it great? Not really, and perhaps that's good enough.