Game jams are social events involving the integration of various game making disciplines (e.g. programming, art, design) to make games under constraints, such as a short fixed time. Game jams are emerging in areas such as research, education, and industry as events to facilitate game making for designed outcomes; i.e. outcomes elicited from appropriately designed game jams. Game jams continue to grow and be appropriated to new contexts, however, little is known about how to design game jams to facilitate designed outcomes. We identify participation in game jams as a constructive form of play defined as ludic craft. Consequently, we investigate the properties (e.g. rules) of game jams under the lens of play on the playful vs. gameful continuum. Reflecting on our experiences as facilitators and participants of jams in indie, industry, and academic contexts, we have derived a set of guidelines for game jams to facilitate ludic craft in its playful and gameful forms. We present this set of guidelines for jam facilitators to cultivate experiences that support designed outcomes in contexts such as research, education, and industry.