You likely haven't read the in-game notes. If so, you can find a brief summary of the game's plot in the description on the itch.io page.
My game has a complex story: the player is a parasite living in the human brain. As time goes by, the brain starts to deteriorate and the world around the player suffers. You can find the game's story in the description. Thanks for your feedback! Next time, I will try to come up with a more interesting story than the one in the notes.