This study aimed to discover the lived experiences of Serious Game designers. More specifically, how they incorporate higher-order thinking skills, as defined by Revised Bloom's Taxonomy (2001), and assessing these skills. The main research questions are: "Which Serious Game design principles allow for the incorporation of higher-order thinking skills?" and "How are Serious Game designers assessing higher-order thinking skills in their games?" This qualitative phenomenological study was based on interviews with Serious Game designers. The sampling of this study was criterion sampling, in which participants are chosen based on the fact that they meet all the necessary criteria. The interview setting was over Zoom with Serious Game professionals from North America and Europe. Interviews were recorded with QuickTime Audio Recorder, transcribed with the website TranscribeMe, and analyzed on Microsoft Excel. The study's participants gave various answers to the three sub-questions but showed several areas of overlap or saturation. Regarding sub-question A, principles of Serious Game design include incorporating learning objectives and understanding the context of the audience. Regarding sub-questions B, to incorporate higher-order thinking skills into a Serious Game, the designer must create a sufficient system and give agency to the players. Lastly, sub-question C, regarding the assessment of higher-order thinking skills, are primarily assessed through qualitative means. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]