Stranger Things Season 2: What The Ending Really Means

10. The Gate Is Closed

Thanks to Eleven learning that her command of her powers is greater than she imagined (probably because she was partly haunted by what happened the last time she used them in a big way), the main gate to the Upside Down is now closed, and the Mind Flayer has seemingly been trapped in his own realm.

Damn right, Eleven should have been the one to close to tear between dimensions - it was, after all, her that opened it in the first place, and this was as much a symbolic gesture to her coping better with what she is and what she can do as it is her being all heroic.

From the way the climax is framed, it seems that the gate closing is a definitive thing - that there is no way for the Mind Flayer and his minions to get back through. It was enough to sever the connection between the big bad and his demodogs, after all, so it must have been pretty final. But wait...