This paper describes the methodology and results from a Systematic Literature Review (SLR) of the software processes used in game development. A total of 404 papers were analyzed as part of the review and the various process models that are used in industry and academia/research are presented. Software Process Improvement (SPI) initiatives for game development are dis-cussed. The factors that promote or deter the adoption of process models, and implementing SPI in practice are highlighted. Our findings indicate that there is no single model that serves as a best practice process model for game development and it is a matter of deciding which model is best suited for a particular game. Agile models such as Scrum and XP are suited to the knowledge intensive domain of game development where innovation and speed to market are vital. Hybrid approaches such as reuse can also be suitable for game development where the risk of the upfront investment in terms of time and cost is mitigated with a game that has stable requirements and a longer lifespan.