Darby Days is a light-hearted adventure. It was orignally run at a con as a single event game. It is rather ''directed'' since it is intended as a single-session adventure. Darby Days is born out of a hobby that the authors' share and a desire to do something a little different than a campaign style game.
When run originally, the playing group was rather large, 12 PCs, and was a mix of various professions. This need not be, as the power level is easily adjusted.
The GM duties were split between two people, with one playing (to the hilt) the NPCs. With this split, an interesting thing happened. Often, PCs will interact with the GM out of character and this can detract from the role-playing experience. However, by having a co-GM playing the NPCs, the interaction between the NPCs and the PCs seemed to enhance the role-playing of the PCs.