Technical debt is a term that describes the consequences of taking shortcuts or quick-and-dirty solutions in the software engineering process, in order to gain short term advantages in the development process of software projects. In this paper, we investigate the technical debt present at the fintech company Adyen, and the developers' experience with technical debt. We investigate their behavior towards testing and refactoring, and give insight into module health with the Delta Maintainability Model. With the conclusions from this research, we propose a novel gamification system called 'Code Karma' to address these technical debt issues, give insight into efforts that increase code quality and motivate developers to improve internal software quality. We found that the Delta Maintainability Model may be used to evaluate module health over time. Additionally, developers believe that 'Code Karma' has a positive influence on the internal quality of the system.