The architecture of your multiplayer Tetris game demonstrates a commendable iterative development process, starting from vanilla JavaScript and progressively incorporating more robust solutions like TypeScript and PixiJS as complexity grew. The use of Architecture Decision Records (ADRs) for significant choices such as language, rendering, and testing strategy (ADR#02, ADR#03, and unit testing ADR) is a strong practice, ensuring clarity and rationale behind architectural shifts. The initial component design provided a good separation of concerns for shapes, player actions, and game rules, which has been built upon.

My evaluation process involved tracing the project’s evolution through the blog posts. I noted the transition from a single JavaScript file to a more modular TypeScript structure, the strategic adoption of a rendering library to manage complexity, and the introduction of unit tests to improve code quality and maintainability. The current architecture is well-suited for the initial goal of a local multiplayer game.

To improve, consider further modularizing the core game logic, potentially extracting state management into a more defined module to prepare for complexities like network synchronization. Abstracting input handling away from direct keyboard events will be beneficial for supporting different input methods or networked play. Finally, formalizing the game state into a serializable format will be essential if you plan to expand to multi-device multiplayer, enabling easier transmission and synchronization across clients.