Eleven had those powers because the government did LSD, etc., experiments on her mom while she was pregnant?

Come on, man! I was thinking for sure that they were going to explain it that she somehow gained those abilities during all of her interdimensional travel stuff/experimentation as a kid at the evil Hawkins Lab. Seems like it would have been a much easier sell because of the completely unknowable effects of a parallel dimension or whatever. But secret government experiments when she was en utero? Weak.
Some of the kids were entirely too fearless as well. It is somewhat understandable that Jonathan would go out in the woods with a gun looking for the monster because his little brother was missing. Nancy though...she, the 90 pound teenage girl, goes out there to take on some monster with a fucking baseball bat because her ginger friend is missing? Really? And she crawls into the tree when she find the weird, creepy organic gate thing? Are you kidding me? No way in hell she crawls into that thing, especially since she has to assume the monster is responsible for it and could well be waiting inside to kill her or that it was a trap created by the monster...like a spider web type of thing. No one is that brave and/or stupid.
There is a lot of stuff like this. Like I said, I made the decision to just pretty much ignore most of this kind of stuff and just enjoy it. And I did enjoy it. There were just some things that I felt like they probably could have tried a little bit harder to make somewhat believable is all.