Multi-level adaptation in end-user development (EUD) is an effective way to enable non-technical end users such as educators to gradually introduce more functionality with increasing complexity to 3D virtual learning environments developed by themselves using EUD approaches. Parameterization, integration, and extension are three levels of adaptation ranging from straightforward to complex in terms of what end users have to understand in order to develop functional software applications, all within reach of end users without special training on programming. A 3D educational application EUD system prototype, "iVirtualWorld," has been expanded to support 3D virtual chemistry experiments generation using these three levels of EUD adaptation. An evaluation has been conducted on 18 participants from the education domain, and the results confirmed ease-of-learn, ease-of-use, and usefulness of this solution. Contributions of this paper are: (1) a paradigm for applying EUD technologies in 3D virtual learning environment creation; (2) an easy-to-use tool for educators to build customized virtual chemistry experiments; and (3) empirical assessment data for the multi-level adaptation solution.