Yeah, I think Underrail is a fucking amazing game. I'm suffering from the delay in Expedition's release. But even though I think its gameplay is top notch, saying it's better than "any RPG from the '90s" is pushing it too much.
BIG EDIT:
I didn’t look at it that way. I still experienced the content, I just didn’t know what it was referencing. So it was new to me rather than some wink wink reference. Might actually be better that way.
Having the game set in Russia ( and written by Russians) when I know very little about Russia made it more interesting to me.
That's fair, but I'd still say you end up losing some of the content, yes. It doesn't mean that the content that is there is no longer interesting or don't have something new to say, but it does mean that your experience is limited by what you can understand directly from what has been said.
Let's say a certain character is inspired by a certain writer. If you don't know the writer, you will form your impression about the character based on what the game shows you. But if you know the context in which the character was created and the intention behind it, you can have a much more complete and broad view regarding the attitudes of said character, which can even change the meaning of certain attitudes of him within the game for you. Now you have a knowledge that transcends the game, because that knowledge has been left implicit.
The same goes for references to other works, to music, to personalities, to situations or places. Any reference when well used brings more information than what is being said explicitly. This, for example, is a great challenge to translations, it's very hard to be able to translate phrases that maintain not only the literal meaning of what was said, but the parallel and/or alternative meanings. Idiomatic expressions, puns, historical expressions, etc.
So, yeah, you can play a game without understanding the references and still like it, in the same way that you can read a translation of a book and like the book. But if you have the chance to go through this same experience again with the knowledge of the content you didn't have before, what you will experience will be something quite different.