Author here (as some of you know already). I'd love to answer any questions you have!
Which one gives you more money?
I saw that the Command pattern has JS snippets and Prototype talks about JS, but most patterns don't seem to talk about JS.
BTW, JS is a prototypical language wrapped in classical syntax. That syntax exists because of Sun & Java's intervention. I find that using most of the language constructs there lead to more brittle code than writing it yourself. Object.create() might not have been in the language since the beginning, but it's here now, and it's what should be used.
"You don’t see many games where each monster is a unique snowflake, like “sort of halfway between a troll and a goblin with a bit of snake mixed in”."
You don't see many games where that's the case because classical programming makes it hard to do that. Programming with classes makes you think of homogenous classes of stuff, and that leads to homogenous stuff.