The global gaming industry, especially the mobile game market, has grown rapidly in recent years. One of the important characteristics of mobile games is that their lifetime is remarkably short compared with those of PC or console games, and downloads of most games peak during the early period of the service. Acquiring as many users as possible immediately after the launch and retaining these users therefore becomes very important for the successful performance of mobile games. This study aims to identify the determinants of mobile game success during different periods after the launch by comparing the first week's performance with the first 4 weeks' performance using a multiple regression analysis with mobile game application downloads from Google Play and estimated sales revenue as performance indicators. The predictors were classified on the basis of the pre- and postlaunch phases, and developer/publisher and third-party factors. A key finding is that for both revenue and downloads, TV advertising and the number of online videos have strong impacts on both the first week and 4 weeks' performance. In addition, preregistration during the prelaunch stage is effective for increasing both revenue and downloads in a relatively short time. Online videos uploaded by the users during the postlaunch phase may help to maintain long-term revenue. Although awareness of IP and name value of publishers are significant for short-term downloads, the effect diminishes after a month, which might imply that there could be an opportunity for small- and medium-sized companies to invest in media and obtain mobile platform advantages in the long run.