I thought this episode was quite atmospheric and very entertaining, with the right beats for character development, all this enough to rate this a "9" despite the pastiche-y nature of the thing.
I did have to turn up my suspension of disbelief with the Gorn in a number of ways, as the depiction bordered on silliness at times. I think the apparent inconsistencies in Gorn depictions in their handful of appearances or mentions in the franchise are best explained by having multiple types/species/whatever of Gorn within their Hegemony. It is certainly hard to picture these extremely fast and agile, juvenile Gorn driven by raw animal instinct, growing up into the "highly advanced," slow yet unstoppable force of brute strength that was depicted in TOS "Arena."
Here's a bit of retcon-logic... Kirk referred to the reptilian captain he encountered as "the creature
the Metrons called a Gorn." Maybe he had heard vague rumors and reports of the type of Gorn that Pike had encountered, but this one was different enough that he didn't quite take it at face value that it was actually the same thing.
By the way, let's dispense with notions that the TOS Gorn is 'silly' or 'cheap' or whatever, and give credit where credit is due for Wah Chang's work on the design and the costume. Michael Westmore noted that the TOS Gorn captain "was a very advanced creation for his time." And it was meant to be slow and lumbering per the script; think how silly it would look for something like the classic Godzilla to dart around like a little lizard.
Also, a frozen-solid body with bones wouldn't actually shatter into ice dust on impact like that when struck with a hard object.

But that's obviously an homage to well-known Hollywood depictions. So I guess we can let that slide.
Though uneven at times, "Stranger Things" is quite a fun homage to 80s pop culture. Even for me, and for the most part I generally can't stand 80s pop culture. It took me four years to convince myself to finally give the series a try.
Kor