This study discusses the development and effectiveness of game instruction on mathematical communication skills. This feature, developed using Microsoft PowerPoint, provides learning instructions with a chain game called algebra dominoes. The principles of independent learning and mastery learning are strategies in learning to ensure that students can learn independently during the COVID-19 pandemic. This study was developed based on Research & Development with systematic, comprehensive, and coherent stages through strict quality control through the Analysis, Design, Development, Implementation, and Evaluation (ADDIE) design. The results showed that the domino algebra developed was feasible to be mass-produced and used in mathematics learning based on expert validity tests, user practicality tests, and effectiveness tests on students' mathematical communication skills. The effectiveness test results show that the algebraic dominoes games developed are proven to be useful in developing students' mathematical communication skills. The results showed that the increase in students' mathematical communication skills in the experimental class was better than in the control class. The use of game instructions can be the main alternative in designing mathematics learning during the COVID-19 pandemic, both online and offline.