Take a peek at the back of the box - You can see Hopper's Chevy Blazer, Christmas lights arranged on the wall, and Dustin and Lucas minifigs hanging out.
The set is, incredibly, carefully designed so you can stand it right side "Real world" up, or "The Upside Down" can be on the top and the real world on the bottom.
The set includes 8 minifigs: Eleven, Mike, Lucas, Dustin, Will, Joyce, Hopper, and the Demogorgon.
I would love to host a few rainy autumn Sunday afternoon "Stranger Things" LEGO parties where I put out beer, wine and snacks and invite friends to come help me put this set together!
You can check out a video by EvanTubeHD where he unboxes the Stranger Things Upside Down LEGO set and then puts the whole thing together, in time lapse.
You might also enjoy checking out BrickVault's review of the Stranger Things Upside Down LEGO set.
And lastly, here's LEGO's official promo video for their collectible Stranger Things Upside Down set.