Stranger Things Eleven
Eleven (Millie Bobby Brown) in Stranger Things' seventh episode. Netflix

For the most part, critics and fans have loved the return of Stranger Things, the second season of which went live on Netflix this past Friday (27 October), but one episode has proven particularly divisive.

Without delving into spoilers quite yet, the show's seventh episode - The Lost Sister - is a standalone episode focused solely on Mille Bobby Brown's Eleven. The problem some viewers have had however, is that it immediately follows the show's biggest cliffhanger.

Now, in response to the backlash, the show's creators Matt and Ross Duffer have defended the episode.

"Whether it works for people or not, it allows us to experiment a little bit," Matt told Entertainment Weekly. "It's important for Ross and I to try stuff and not feel like we're doing the same thing over and over again.

"It's almost like doing a whole little other pilot episode in the middle of your season, which is kind of a crazy thing to do. But it was really fun to write and cast and work on."

Warning: Spoilers for Stranger Things 2 episodes six and seven follow.

Episode six - The Spy - ends with several main characters facing the prospect of surviving an onslaught from dozens of demogorgons that are about to enter the government research facility outside the town of Hawkins.

The next episode follows Eleven as she travels to Chicago to track down her "sister" Kali - someone else who was detained and experimented on at the facility, and who has developed her own special abilities.

We follow the pair, and the rest of Kali's group, as they use Eleven's powers to track down those who worked at the facility when they were held there. At the end of the episode, Eleven heads back to Hawkins to save her friends.

It's an entirely separate story that fleshes out the show's world and potentially sets up some plot threads for season three. Episode eight begins precisely where The Spy left off.

"Our test of the episode was we tried to pull it out of the show just to make sure that we needed it because I didn't want it in there as filler - even though some critics are accusing us of doing that," said Matt.

"But Eleven's journey kind of fell apart, like the ending didn't work, without it. So I was like, whether this works or not, we need this building block in here or the whole show is going to collapse. It's not going to end well."

Ross adds: "That Eleven story line overall is sort of the biggest risk we took. We're going to continue to do risks moving forward to keep us on our toes. I didn't want her to just magically save the day. Just like Luke Skywalker, she needed to go off on her own and learn something about herself."