The book "Personality Types" by Don Richard Rizo was very entertainingly written and gives you a lot of easily remembered mental hooks to remember catagories by.
He uses his Jesuit background well in his "opposing types combined to form a third type or synthesis". And he did a beautiful job of relating it to some of the major historical writings.
My question comes down to can you really use this in analyzing how a person is going to act based on observations and answers to questions (which is what you have to do in your personality quiz).
Does the character traits of "Artist", "Thinker", "Leader", "Helper", "Loyalist", "Peacemaker", Generalist, "Status Seeker", or "Reformer" give us enough information to tell whether the person will help when asked, actively help, reliably help, be fair, or even help when it is against his/her current interest (which is what you want in both life and the computer game)?
I haven't seen a better method yet but can the Enneagram be used for the quiz?