21 questions we hope will be answered in 'Stranger Things' season 4

Some fans believe "the American" we heard about being kept in a Russian cell in season three's mid-credits scene is actually Dr. Martin Brenner, aka Eleven's "Papa."

We last saw the real Brenner (not a supernatural projection of him) on the season one finale when the Demogorgon leapt onto him. Technically we never saw him die, nor did we see a body.

As the second season (and a Collider interview with executive producer Shawn Levy) revealed, Brenner is still alive and out there in the world. But where? Could he still secretly be working for the US government, and Dr. Owens is just a front? Or is he now wrapped up with the Russian government?

We've now been introduced to Kali (008) and Jane/Eleven (011). Where are 001 through 007? Or 009 and 010? What about 012 and up? Does the count of children kidnapped and experimented on go into the 100s?

When Eleven was looking through her mother's files, several newspaper clippings on other missing children included reports of both infants and teenagers being abducted. Were those other kids with powers? Or was Terry Ives only right about Kali?

We need a lot more answers about how these experiments have been carried out.

Back to the questions surrounding Hopper, we still don't know the details of the deal he made with HNL and Dr. Brenner at the end of the first season.

He sold out Eleven's location in order to save Will, but then later we saw him get into the backseat of a black car without a word. Who was in the car? And why did Hopper seem unsurprised to see them?

There is something strange about Hopper's daughter, Sara, and how her death in a hospital might have actually been HNL itself.

The staircase where Hopper was shown crying over Sara's illness is the same staircase seen inside HNL on "Stranger Things 2." Actor David Harbour (who plays Hopper) also pointed out that similar stuffed animals are seen on Sara's hospital bed and inside HNL.

"So yes — there is a connection there perhaps that we may go into further down the line," Harbour told Insider in an interview.

Based on the show's timeline, the Russian scientists had a version of their machine built by about seven months after Eleven accidentally opened the Gate inside Hawkins National Lab (HNL).

So how did they know about the Upside Down? Did they somehow find out about the accident at HNL and then work on finding a way in? Or was it a total coincidence that they were developing this technology?

Joyce and Hopper visit HNL and don't see any sign of activity. They simply see the concrete-covered wall where the Gate used to be.

But we know the Russian lab entrance is far beneath the Starcourt mall, and then a long hallway leads to the place where the Gate is. But where is this new Gate in relation to the rest of Hawkins?

"In Hawkins, this door had been opened once," Murray says while interpreting for Alexei. "It was still healing."

This makes it sound like it's the same place where the first Gate was, but if it is then we're confused as to how the US government hadn't realized so much energy-related activity was happening underneath the HNL.

On the third episode of season three, Joyce and Hopper walk through HNL to try and assuage her suspicions. They don't see any activity (though Hopper gets roughed up by Grigori), but there is a blinking security camera in the corner.

Who is watching that feed?

We would have assumed it was Dr. Owens team and the US Department of Energy — but then Grigori shows up. Have the Russians hacked the US government surveillance? Or was Dr. Owens and his team just dropping the ball?

In the opening scene of season three, the portal machine in Russia appears to open to the Upside Down as well. Is that just a coincidence? Or are the only two dimensions the regular world and then Upside Down?

The hospital scene alone in season three showed what looked like dozens of nurses and doctors and patients killed by the Mind Flayer's human minions.

Combine those people with all the Flayed (who presumably died when their bodies exploded), that has to be close to a hundred people killed, right?

Based on the newspaper clippings, it looks like the government is covering up the Battle of Starcourt and the Mind Flayer's gross physical manifestation by claiming an electrical fire was started at the mall.

But how are they going to account for the Flayed people who were seen walking away like zombies on the night of the Fourth of July? And what about the folks in the hospital? One of the news reports notes that citizens of Hawkins didn't fail to notice men in hazmat suits walking around after the "fire," and the conspiracy theories are starting to blossom.

We hope future episodes of "Stranger Things" address just how dangerous Hawkins must feel for the rest of the population now.

"Stranger Things 3" never fully explained why the Mind Flayer was making its victims eat and drink chemicals. Was that just so that their bodies would be piles of goo by the time they died? Couldn't the Mind Flayer have achieved that without the super-conspicuous behavior of having humans gobble down bags of dirt and gallons of bleach?

The kids briefly mentioned that mixing chemicals would "create a new substance" but there are still a lot of questions surrounding the Mind Flayer's plan here.

Was it really promethium, like Dustin guesses? This is a real chemical, but it's extremely rare and the Russians seemed to have a lot of it. Where was it coming from?

We see in the mid-credits scene that the Russians have at least one Demogorgon on hand and they're feeding live human prisoners to it. How did they find out about the Demogorgons? Was it, once again, thanks to the HNL incident? If so, then the Russian spy networks inside the US government are clearly deeply seeded.

Also, are there multiple Demogorgons? Does every little Demodog grow into a Demogorgon?

Back at the end of the first season, Eleven appeared to blow up a Demogorgon (and then vanished alongside it). But the second season revealed that she had actually just gone into the Upside Down.

Did the Demogorgon survive, too? Or was that one killed and the one we saw in the Russian prison is a different creature?

Dustin insisted on putting the dead Demodog in a fridge to preserve it, since it was the best piece of physical evidence they had proving the Upside Down was real.

But where did it go? Did the HNL team take it?

As far as the show has revealed, the Mind Flayer is at the top of the supernatural food chain inside the Upside Down. He controlled the Demodogs we saw on season two — so does the Mind Flayer also have control over the Demogorgon?

If so, how does this work when the Gate is closed? Shouldn't the Demogorgon be dead if its link to the Mind Flayer was cut off?

When Dr. Owens and the US Army arrived at the Russian Lab, there were no soldiers or scientists around. Was that just a stylistic choice for the drama of the scene? Or did all of the Russians really survive and escape unseen?

How would they have gotten out of the underground facility without anyone seeing?

Dr. Owens took over the HNL after the first season's disastrous events, saying he wanted to try and rectify the "mistakes" made. But now an even more cataclysmic disaster has struck Hawkins.

What is the plan now? More cover-up and secrets? Do they not want to involve Eleven, even though she theoretically has the best understanding of the Upside Down and the Mind Flayer?

We don't know who the sacrificed man is, nor why the Russians were feeding him to a Demogorgon. Are they conducting more research on the Upside Down? How many Demogorgons do they have?

Eleven lost her telekinetic and other supernatural abilities after she expelled the piece of the Mind Flayer's body from her leg. But why did that impact her powers? And how would they return?

Perhaps there's an emotional blockage happening since she's understandably experiencing some post-traumatic stress. We doubt Hawkins and the world at large would survive another Mind Flayer attack without her, though, so hopefully her powers return soon.

• Read more:
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• 14 reasons why Hopper is almost certainly alive
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