Eleven Closes the Gate
While part of the group is preoccupied with curing Will - and the rest of the kids, plus Steve, make themselves useful by luring the Demodogs away from Hawkins Lab - Eleven and Hopper have the most difficult task: closing the Gate and trapping the Shadow Monster in the Upside Down. However, as revealed earlier in season 2, the Gate that Eleven opened prior to the events of season 1 has grown exponentially bigger. Not to mention, the Shadow Monster has a whole host of Demodogs under his control, which he uses to try to prevent Eleven from closing the Gate.
Of course, Eleven has Hopper - and his many guns - on her side; using the method of channeling her powers as taught by her "lost sister," Kali (Linnea Berthelsen), Eleven is able to close the massive Gate that has grown and expanded below Hawkins Lab. As a result of Eleven closing the Gate, the Shadow Monster's connection to his army in the real world, which largely consists of the Demodogs and the vines growing in the tunnels beneath Hawkins, are defeated. It's unclear if the Demodogs and the vines die, but they certainly appear to be gravely wounded. The Demodogs that had been attacking Hopper and Eleven in the shaft under Hawkins Lab begin falling, and Dart is shown lying on the ground in one of the tunnels.
Further, as shown in the epilogue immediately following Eleven closing the Gate, Hawkins Lab is designated a restricted area by the Secretary of Defense - a branch of the government - and the building becomes off limits. Does this truly mean Hawkins Lab has shut down and the government has ceased the testing that led to the Gate being opened? Likely not, but considering the amount of damage done to the facility by the Shadow Monster's army of Demodogs, it's understandable that the government would just cut their losses and move elsewhere. Or, as the case may be, shut down the project altogether now that the Gate is closed and Dr. Brenner (Matthew Modine) is still in hiding. Though, with Brenner confirmed to be alive, we definitely haven't seen the last of him.
What that means for Eleven and her friends in Hawkins seems to be that they're relatively safe for the time being. There aren't any obvious remnants of the Shadow Monster in Hawkins - at least, as far as viewers are shown in the epilogue for 'The Gate'. But, that doesn't mean Stranger Things has shown viewers everything.
As far as teases for what's to come, there's little in the epilogue at the end of the season 2 finale. However, the sequence does wrap up a number of character storylines that were developed throughout the season. One of the biggest revelations is that Dr. Owens (Paul Reiser) made good on his promise to Hopper and offered Eleven a chance at a normal life by forging a birth certificate for 'Jane Hopper' - combining Eleven's original name as given to her by her mother, Terry Ives, with Hopper's last name. Additionally, though Owens urges Hopper and Eleven to lay low for another year (indicating how much time will pass until the next season of Stranger Things), Hopper allows El to attend the Snow Ball at Hawkins Middle School, where she dances with Mike.
At the Snow Ball, 'The Gate' also seems to establish Nancy and Steve are no longer together, which makes sense considering her and Jonathan (sort of) admitted their feelings for one another. Lucas asks Max to dance, and the two share a kiss. Dustin, meanwhile, winds up dancing with Nancy after being rejected by a few of his classmates. Still, it seems both Nancy and Steve have taken Dustin under their wing, which will undoubtedly have an interesting - and, likely, humorous - effect on him in future seasons. Outside the dance, Joyce and Hopper share a cigarette, with the former still dealing with the death of Bob Newby (Sean Astin).
However, if viewers were lulled into a false sense of security by the wholly normal epilogue, the final scene of the season 2 finale features an exterior shot of Hawkins Middle School that rotates until the Upside Down version of the school is revealed. Though the alternate dimension seems quiet at first, a storm brews and lightning reveals the Shadow Monster looming over Hawkins Middle School - no doubt a visual representation of the evil monster biding its time until it's able to try to escape the Upside Down once more.
So, while Stranger Things largely wraps up its storyline thus far in the season 2 finale - even giving season 1 fan-favorite Barb (Shannon Purser) a funeral of her own - there's obviously more to come for the residents of Hawkins, Indiana. Certainly, the revelation of Kali earlier in season 2 leaves the door open for more individuals with abilities like her and Eleven to be alive and living elsewhere; even if they're the only ones, Kali's mission to exact vengeance on all the Bad Men will no doubt resurface at some point. Plus, with the Shadow Monster not yet defeated, it will rear its scary head once more. But viewers need not worry, as the Duffer Brothers have plans for further seasons already in the works. Until then, share your theories about what will happen in Stranger Things season 3 in the comments!
Stranger Things seasons 1 and 2 are currently available in full on Netflix.