Thanks so much for playing - and for giving this such thought! I'm still planning to come back to it at some point (both Draw Nine itself, and hopefully the same basic idea for another game). It's tough to write because each step of the journey needs two locations and each of those locations needs four outcomes for the cards, but at the same time that does at least mean that the story will never branch uncontrollably.
I'm afraid I can't spot that mention of the serpent in the passage where you use the spider card against the manticore - there are two versions of the encounter so a fair bit to check through. Do you happen to remember if you saw it in the version where the manticore is defeated or the one where you just run away?