You know, someone else gave me similar feedback as well. I'm kind of reluctant to make it longer, but might be a better story if it is. Like: maybe have something about the government responses to it and what happens, etc, work some of the explanations in there. Going to keep this in mind, appreciate it!

Just to be contrarian, I like the ending. Always be wary of over-explaining in stories, especially in science fiction.

I find that you can trust the reader to deduce a lot of what you are explaining without having to explain it.