The Delving Deeper Referee Guide is short, sweet, and to the point but also useful and inspiring (which are the two most important qualities for any referee/DM/GM guide). It dives right in to creating a world, and the frameworks given are the perfect skeleton upon which to hang the flesh of your imagination. I can't comment on whether Delving Deeper nails the feel of "OD&D" or not, but I can say Delving Deeper captures the spirit of bringing friends to a table to create dynamic characters and adventures without being burdened by excessive rules and game mechanics.