This was a really cool idea, and I enjoyed the theme and the visuals/music. I was pleasantly surprised by both of them, and the story certainly didn't hurt either.
Where it fell short for me was the gameplay, which, while it seemed fun, the buttons only sometimes worked(and pausing to read the instructions didn't). My biggest problem was how the game ran though. It seems like everything the *player* does runs in an 'Update' script call, right? The problem with that is that, on the browser the game ran way too slow, andI couldn't do anything while human forces built up around me. When I downloaded the game, it ran much, much faster. For me at least. For the humans, they couldn't keep up as the mycelium spread like a plague, all while I wasn't doing all that much.
It's a shame these controls/the way the game ran caused me issues, because otherwise it was a fun game!