As far as logic goes, I totally agree, but personal preference nit pick, from a code writer and reader perspective, I think all subproperty access (`hero.acceleration.x`) could be cached to a variable, or just operate on plain variables and assign property access after mutations and only manipulate objects as needed.
It makes the code easier to write and read, IMHO, and I believe older engines had infinitesimal changes in performance with updating objects, so it's more of a habit and code clarity thing for me.
Of course, that's far less important than the fact that the logic is clear and concise, especially after learning JS in a week :)
I love Mark Twain, mostly because of how easy it is to rip him off and ascribe quotes to him.
But also because Tom Sawyer was the first book I had read as a child that put the taste of Southern grass in my mouth and the feeling of thick humidity reaching out and strangling me.
I don't always like writers from past times (the older they are, the harder the mental overhead in feeling the story), but he was one from another time that intoxicated me, even as a "millennial" hooked on comics and video games.
This article and other comments have inspired me to dig a bit more into the man.