The video game industry can be ruthless. As a developer, you usually find yourself working in the popular third-party development tools of the time. These tools however might not provide the best usability and quality of life one desires. This can lead to a lot of frustration for the developer, especially when the development enters a crunch period of long and hard work. We believe some of the frustration can be avoided, and we believe this can be done by creating effective, functional and user-friendly integrated development tools specialized for the development environment. In this master's thesis we investigated just that, how integrated game development tools can be designed to be usable in terms of effectiveness and learnability. The investigation was performed by designing and implementing an integrated game development tool. The development of the tool was performed iteratively with user testing between every iteration to find usability defects, allowing the tool to be refined and improved throughout the development process. To finish off the development process, there was a final user test where professional video game developers tried out the tool and then answered a System Usability Scale questionnaire. The System Usability Scale score and task completion rate showed that the final state of the tool can be considered highly usable in terms of effectiveness and averagely usable in terms of learnability. This suggests that involving user testing in the development process is vital for ensuring good usability in the end product.