Originally Posted by
AvalonXQ
I think people overuse the term "retcon," and this is an example. Giving significantly more details about particular parts of a story isn't a "retcon" unless you have to explicitly or implicitly deny significant aspects of the original story in order to do so. Chapter 2 is a significant "filling in" of particular details but I wouldn't call it a "retcon."
I think changing "plants were created before humans" to "humans were created before plants" qualifies as a retcon. YMMV.