I have chosen to post here because I am not sure of the extent to which the designer of the game is actually prepared to lay out the game yet.

But I had so much damn fun, I had to talk about it.

It is designed to be a multi-chapter game with a final chapter whose essence is determined during game setup: the selection of 1 of the major arcana of the Tarot Deck determines the nature of the final chapter.  There is 1 chapter per player, plus 1 for the final chapter.  The game combines Capes-style GM-less arbitrated decision making with an endgame mechanic.  We finished one chapter tonight and I could easily see this becoming a series of adventures.

SERPENTINE is an occult mystery game involving Tarot cards as a mechanic and as a character generation device.
2 Tarot decks are shuffled together to create the pool used for resolutions.
1 Deck is kept seperate for the creation of characters.

The character creation deck is the Major Arcana.  Collectively, the group decides which card will serve as the inspiration for the final chapter.  (In the playtest it was The Hanged Man, the card of devastating enlightenment).  Every player is then required to write down that card in one of the seven aspects that define your character: Heart, Mask, Obstacle, Fate, Past, Enemy, Ally.  I, for instance created a secret society reaching to create new principles for the new century, one of those creepy sort of aristocratic occult groups that gained a surprising amount of notereity in the radical politics of the early 20th century (like the Thule Society in Nazi Germany, or Evola's bunch of occultists in Fascist Italy, and the "Traditionalist" groups associated with Romania's Iron Guard).

You then take a few more rounds to place a few more cards in the slots on your character sheet.

Everyone has some characteristics that are solely their own but they share many with each other.  Moreover, they create NPCs who share some of their characteristics.  Other NPCs are a meld of characteristics chosen by 2 players

Resolution takes 2 forms:
A simple Investigation scene where some aspect of the character is revealed -- represented by the addition of a Major Arcana card to that character's personality.  This is resolved by a 3-round Whist variant.  2 characters can, if they conspire, make changes to other characters.
A complicated Conflict, where a character may gain, lose, or have shuffled 1 characteristic.  Such a conflict is resolved with a 7-round Whist variant.
If the player setting the scene deploys his or her chapter-ending card, the Conflict marks the end of the chapter. 

Each player gets a Major Arcana card that allows he or she to provide a closing to one of the chapters of the story.

I was able to bring my loopy secret society into the heart of things when I played the Empress, on which I had written the omen "Lady Gregory signs an important document." In the rush of conflict resolution that followed, an opium dealing Chinese gentleman provided the poison which was later administered to Lady Gregory after the coach carrying her through London was attacked by rioting strikers, strikers getting money from the secret society ("The Silver Hand of Nodens") and from a group of criminals.  The medicine was accidentally administered by an ambitious but debauched doctor, friend of a fellow doctor in Reading Gaol for having murdered several of his patients. 

Plenty of material introduced by the other players was still unresolved.  Why did Lady Gregory choose to fund the Antarctic expedition of the incompetent explorer Babbage?  What was the role played by the wealthy financier Robert Greenwald, a man seen in the company of criminals and with connections to The Silver Hand?  And what was up with the Inspector who was seen pulling a confidential file out of the hands of the over-curious junior clerk?

I don't know how these pieces will come together.  But when I saw how the chapter ended, I knew that they would.

I hope the designer takes the time to post more detailed descriptions of the mechanics..

From a comment posted to the IndieRPG Toronto Message Board

Last night, during Serpentine, I said I found a need for more investment in the gamey-parts' outcomes - either by mechanical incentive (such as Capes "gimme some Story Tokens and Inspirations!") or character identification (ala MLWM's pathos-driven minions).

To which Eric said, "What about 'story'? 'Which story is cooler?' "

To which I replied, "Eh, not for me. Steve's story and Mark's story are equally cool, how do I decide?"

This morning, it occurs to me that this isn't quite right. I should have said: That could work, in situations where the stories I'm choosing are plainly visible - in Serpentine, where two trick-winners negotiate for control. But, it doesn't, by itself, get me motivated for the gamey-parts: Should I trump this trick? Should I throw off a low card?

So, yes, Erik's right; there's three ways to perk my investment.

I was thinking about how to make dramatic changes in the cast of characters.

Remember, mysteries depend on the elimination of subjects as well as elaboration of their involvement in the crime.

Could you reduce a major character to a minor by stripping away attributes, so that they are reduced to one or two cards or even none and thereby pushed out of the pool of NPCs?

And how do you kill a character?