In this paper, we describe an in situ study that examined the diverse design features and effects of three pre-algebra games for middle school children who have either challenges with learning or different language backgrounds. Data were collected through in-field observation, artifact analysis, school performance report and knowledge test during 15 one-hour gaming sessions over a period of 3 weeks. A list of key design features related to creating engagement and learning for students with special learning needs emerged from the data. The findings and discussions will inform educational designers and practitioners on successful educational game design and implementation for learners with diverse characteristics and needs. (Contains 5 tables and 3 figures.)