Well, I did the whole quest (without finding the quest log because the game is too big for my browser window), then had one goblin left and clicked "menu" to see what it would do and was forced to start over. However, I think I've now broken the quest progression...
[SPOILERS FOR THE QUEST]
I moved the windmill blades before talking to the miller. His daughter showed up and she sang her song but wouldn't say anything about feeling calmer. I went through the quest progression again afterward, but after talking to the miller the daughter's dialogue didn't change, and I don't think I can do anything else. That means I'm locked out of the tree goblin as far as I can tell.