As a chick from the '80s, I was singing along with them and I really enjoyed the episode. I know one reviewer said nothing really happened, but I think they just weren't paying attention. And if they already don't like musicals I can only assume they were a millennial or a Gen Xer that doesn't know good music when they hear it. Don't pay attention to the negativity, this episode definitely moved things along, although I don't see how they will finish everything in the finale.
I'm very sad that there's only one episode left, and I'm pretty sure I'm going to have to go back to the beginning and re-watch the whole series because I will miss The Magicians.