More '80s than a John Hughes movie marathon, Netflix's Stranger Things was the surprise TV sensation of 2016. Seriously, post-July, people just wouldn't shut up about it.

Eleven, the Upside Down, the Demogorgon, Steve Harrington's hair... All became iconic overnight.

Six weeks after the first eight episodes dropped, Netflix confirmed a second season (though it later transpired that they'd been lying to us, the swines, and had already ordered more before the show had even launched).

Here's everything we know about the much-anticipated sequel to the Duffer Brothers' loving tribute to Spielberg, Carpenter and King.

Stranger Things season 2 air date: When can I watch?

Netflix has confirmed that we'll be returning to Hawkins for more freaky goings-on this Halloween. Originally billed for an 31 October, 2017 premiere, we're now getting Stranger Things season 2 a few days earlier – so 27 October, 2017.

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Filming on the new episodes finished up in late May, with Noah Schapp (Will), Millie Bobby Brown (Eleven) and more posting wrap messages to social media.

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Stranger Things cast: Who's back, and who's joining the fun?

Of course, the boys are back: Finn Wolfhard as Mike, Caleb McLaughlin as Lucas and Gaten Matarazzo as the inimitable Dustin.

There'll also be a whole lot more of Will now that he's returned, transformed, from the Upside Down – with actor Noah Schnapp promoted from recurring to series regular.

Winona Ryder is returning as frazzled Joyce Byers, as are Cara Buono as Karen Wheeler and David Harbour as Jim Hopper (though surely the haunted cop hasn't really turned to the dark side?).

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And things won't be getting any easier for Nancy Wheeler (Natalie Dyer), with both moody outsider Jonathan Byers (Charlie Heaton) and reformed douchebag Steve Harrington (Joe Kerry) still on the scene.

But will Stranger Things still be turning things up to Eleven? Of course it will – the door to the Upside Down is still open and Millie Bobby Brown is confirmed to be reprising her role as the sweet but terrifying telekinetic wonder.

There'll be no #Justice4Barb though, with director Shawn Levy warning that any fans hoping for a resurrection "will be disappointed"...

... And that includes Barb star Shannon Purser, who cheekily asked the question at Comic-Con 2017. (Spoiler: she didn't get the answer she wanted.)

Series creators Matt and Ross Duffer have confirmed though that while Purser's beloved geek will stay dead, she "will not be forgotten" - while Purser herself told Digital Spy that she's open to appearing in a flashback.

Despite his apparent death at the hands of the Demogorgon, "Bad Man" Brenner (Matthew Modine) is also being revived for season two, though he'd better watch his back...

"If the Monster is dead, was it a singular monster?" teased Matt Duffer. "What else could be out there? There's a lot more mystery there to be solved."

But wait, there's more! Stranger Things will be bulking out its cast in 2017 with some new additions: tough 13-year-old girl Max (Sadie Sink), her cocksure stepbrother Billy (Dacre Montgomery) and the mysterious Roman (Linnea Berthelsen).

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[Above: New cast members Sadie Sink and Dacre Montgomery]

Nashville's Will Chase will also play a "pivotal" role in the new series, starring as Neil Mayfield, the father of a new family from California who move to Hawkins, Indiana - could he possibly be Max and Billy's father?

Character actor Brett Gelman, who's appeared in everything from Fleabag to Matthew Perry sitcom Go On, has been hired to play "a disgraced journalist-turned-conspiracy theorist who is investigating a cold case" in Hawkins.

And there'll be a few more '80s icons joining Ryder and Modine, too: starting with The Goonies favourite Sean Astin, who'll play Bob Newby, a kind-hearted nerd who went to high school with Joyce (Winona Ryder) and Hopper (David Harbour).

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Newby now manages the Hawkins RadioShack and is in a relationship with Joyce. "Bob is new to our weird Hawkins group, but he's immediately memorable and I think people are going to be very surprised by where that takes them this year," said Levy.

Then there's Paul Reiser (Aliens), joining the series as Dr Owens – a high-ranking member within the Department of Energy on a "clean-up" assignment, tasked with containing the events of last year.

Owens is an ambiguous character, Reiser has revealed. You're not sure if he's a good guy or a bad guy – though he's got more "a little more humanity" than Dr. Brenner.

"My guy is much more hands-on and among his many degrees is that he has a bedside manner that Modine's character did not have," the actor explained.

We'll also meet a creepy new character named Keith, an employee at the local arcade who is "several years older than our boys, but somehow less mature" and is fixated on Nancy.

Stranger Things episodes: How many can we expect?

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There'll be nine episodes in season two - and we even know what they'll be called:

1 - 'Madmax'

2 - 'The Boy Who Came Back to Life'

3 - 'The Pumpkin Patch'

4 - 'The Palace'

5 - 'The Storm'

6 - 'The Pollywog'

7 - 'The Secret Cabin'

8 - 'The Brain'

9 - 'The Lost Brother'

You can read our rampant speculation here on what these episode names might giveaway about season two – though the Duffer bros. have cautioned that the titles may change before the season drops.

The Duffers will helm the first two episodes, with Levy – who directed episodes 3-4 of season one – back in the same slot for season two.

Finding Nemo and Wall-E director Andrew Stanton will join the fun for episodes 5-6, with Electrick Children's Rebecca Thomas tackling episode 7 and the Duffers' back in the director's chair for the final two outings.

Stranger Things season 2: Is there a trailer?

First, we got an early teaser in late 2016 – scored by Kyle Dixon and Michael Stein's synth-tastic theme tune:

preview for Stranger Things 2 | Netflix

Then, Netflix dropped our first proper trailer during Super Bowl LI – Eleven's back, the boys are obsessed with Ghostbusters and, by the looks of things, Will is still somehow linked to the Upside Down:

preview for Stranger Things season 2: First trailer

A further teaser landed in July 2017, to announce the Stranger Things Comic-Con panel...

And then finally – finally! – we got our first proper trailer at the San Diego convention. Check it out in all its glory below (unless you just ate):

preview for Stranger Things season 2 Comic-Con trailer

The series still seems to be infused with its trademark aura of mystery as it picks up in the aftermath of Will's miraculous return from The Upside Down.

And while all seems well on the surface, there's still something very wrong with Will which we see first hand in the trailer when the poor guy gets sucked momentarily back into (what appears to be) The Upside Down and we're warned that "something's coming".

Will the return of Eleven who we see literally burst through the Upside Down provide the answers that Mike and his pals desperately seek to save Will once again?

Stranger Things spoilers and theories: What's going to happen next?

Stranger Things fan theories are so plentiful that they now form approximately 23.8% of the entire internet. Honest.

We've got our own thoughts as to what went on in the first eight episodes, and what might be coming in season two – which you can read right here. Warning: possible spoilers!

In the meantime, here's what we know 100% about season two (and that's a real stat):

It'll be set in late 1984, a year after the events of the first season, and will venture outside of Hawkins, Indiana. In fact, according to Matt Duffer, "the opening scene [of the premiere] does not take place in Hawkins."

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Could that scene take place in the Upside Down? Certainly, we've only seen "a tiny bit" of the show's dark netherworld, which will be explored "a little bit more" in season two.

"The Upside Down will be more of a place… you'll spend more time [there]," composer Kyle Dixon teased. Part of that will be through Will Byers, who's still somehow connected to the strange netherworld

"He seems to be seeing images from the Upside Down – the question is whether they're real or not," Matt Duffer revealed. "So it seems like he's having some sort of post-traumatic stress disorder."

"[The boys] feel alone because their best friend is back and he's not acting like their best friend anymore. He's changed," teased Gaten Matarazzo.

Finn Wolfhard has also revealed that "something happens to Will in the first couple of episodes that's very, very disturbing".

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Police chief Jim Hopper is desperately trying to keep the Upside Down secret from the community to protect the Byers family. "Hop starts season 2 in a completely different place than season 1," Harbour revealed. "He saved Will and has found a renewed interest in life.

"So his arc for season 2 in my mind becomes more about butting up against the places where his hero fantasy can't take him. The places where that hero complex may force him to make the wrong decisions.

Meanwhile, the breach to the Upside Down remains open, under the watchful eye of newly-arrived government scientist Dr Owens (Paul Reiser).

Two new siblings are also moving into town – Billy (Power Rangers' Dacre Montgomery) and Max (American Odyssey's Sadie Sink). While Max fits in well with Will and his friends, Billy seems to be hiding a dark secret.

"Stephen King always has really great human villains," Matt Duffer teased. "The evil in the real world is often as bad or worse than the supernatural evil, so we wanted to introduce a character like that."

As for the monsters the boys will be facing this season, Finn Wolfhard, has hinted at a "more horror-oriented" second season, while Matt Duffer would only reveal that our heroes will come up against a "different kinds of horror" when Dustin (Gaten Matarazzo) befriends a creature who's literally out-of-this-world.

Shawn Levy elaborated: "I think overall the kind of forces of evil that are inherent in season 2 make that Demogorgon look quaint in retrospect."

"Last season, a lot of the horror and a lot of what was happening with Will was off screen in the Upside Down," Ross Duffer explained. "That's not the case [in season two]. The horror is more up-close and personal."

We'll also dig more into Eleven's backstory – and you can expect some "emotional" reveals.

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Oh, and the new Stranger Things will be "next level" crazy, a "little darker" and "a little weirder" – if we're talking '80s, think of this season as Temple of Doom compared to season one's Raiders...

One theory to already be debunked, though: the show is not looking to cast more Hawkin Lab guinea pigs like Eleven...

The rumour sprung out of a Reddit post that claimed the show was looking for extras who'd be willing to shave their heads... but the official Stranger Things hairstylist later shot down the speculation.

"We actually needed women who would be willing to cut their hair and get bangs, while all the male extras actually needed to grow their hair out," she explained. So, '80s hair then, basically.

Stranger Things season 3: What does the future hold?

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So what's in store for Eleven and the gang beyond season two? The Duffers have indicated that the new episodes lay "the groundwork for further seasons" - in fact, a third season is already in the planning stages.

"We are not gonna be caught off guard," said producer/director Levy. "So we are definitely optimistic and we have started thinking ahead."

So confident are the Duffers' that season two of Stranger Things will actually end on a cliffhanger – leading straight into season three...

A fourth season is also in the planning stages, but that'll likely be the show's final outing." We're thinking it will be a four-season thing and then out," said Ross Duffer, with Matt adding: "I don't know if we can justify something bad happening to them once a year.

"They're going to have to get the f**k out of this town! It's ridiculous!"

From: Digital Spy