My first thought while reading this: Damn, I wish I had the video game. My second: If I keep reading I will already know what happens and I can never be the player who gets to explore this place. My third: Screw it, I need to know what's happening.
I was not disappointed.
I wish I had more to add to the discussion but the other comments have all said what I wanted to and more. I too would love to see a bestiary; when is this happening? ;)
Your descriptions are great and the concepts excellent. Your mind must be a twisted place!