"The smokey strands of the monster recede…" Nice and creepy, especially with all that hairy goo! The story starts out humbly, but the imagery gets gloomier and more ominous as you go. I could feel Trevor’s fear build the deeper he went. Would like to see more emotion in your style—we readers are dumb creatures and really do need to be told & shown how to feel, even though I know that you were feeling it :-)
FYI: you have a bug. The “Turn back.” passage is a dead end, and ends the story. I got stuck there and had to clear cookies & reload to keep playing. I avoided “Turn back.” links when playing again, and was able to finish the game.