This study proposes middleware, GameControllerizer, that allows users to combine the processes of Internet of Things (IoT) devices, Web services, and applications of Artificial Intelligence (AI), and to convert them into game control operations to augment existing digital games. The system facilitates easy trial-and-error development of new forms of entertainment and the configuration of gamification by enabling the use of diverse devices and sources of information as inputs to games. GameControllerizer consists of a visual programming element that uses the Node-RED tool to allow users to program easily to convert diverse formats of information into inputs to games, and contains a game input emulation element whereby hardware- and software-based emulation generates inputs for gaming devices. Evidence of the usefulness of the system was provided by a performance assessment and the proposal of a variety of use cases.