The incorporation of applied games in university differentiated language instruction is increasingly prevalent. This interventional study was conducted through non-crossover design in the academic years 2020-2021 among the students of Isfahan University of Medical Sciences. The quantitative and qualitative data were gathered by soliciting participants' attitudes towards English for Specific Purposes writing through (game)-based differentiated instruction, assessing their academic and professional writing, and debriefing their insight into how differentiated instruction might enhance English for Specific Purposes writing. While the quantitative data were analyzed through Wilcoxon signed-rank test and repeated measures ANOVA, the qualitative data were content analyzed through theme-based analysis. It was revealed that mixed reality harnessed the synergy of augmented reality and virtual reality in English for Specific writing education. Findings showed that single-minded preoccupation with a game type undermines the potential of game-based differentiated instruction in English for Specific Purposes writing. The results and implications are explained.