MHRD is a hardware design game, in which you design various hardware circuits in a hardware description language. The hardware circuits you design get more complex as you go until you create a fully functional CPU design.
The game allows you to create various digital circuits and components using a hardware description language. You start with the basic NAND gate and gradually design more complex circuits, such as logical gates, multiplexers, ALUs, and ultimately a fully functional CPU.
The core gameplay revolves around designing and implementing logical circuits. You use a text-based hardware description language to specify the input/output connections, the internal components (logic gates), and the wiring between them. This allows you to gradually build your understanding of how basic logic gates can combine to create more complex digital circuits.
One aspect players enjoy is the modular nature of the circuit design. You can create and save your own custom components, then reuse them in the construction of more complex circuits. This allows for a sense of progression and a building up of knowledge, as you can leverage your previous work to tackle new challenges. Additionally, the game features an "intern" named Ted who automatically generates 16-bit versions of the 4-bit circuits you design. This helps reduce the tedium of repetitive tasks, letting you focus on the core logic.
Reviewers often highlight the game's educational value, as it provides a hands-on introduction to the fundamentals of digital circuit design and computer architecture. By guiding you through building a CPU from the ground up, using only basic logic gates, the game offers a unique and engaging way to learn these concepts.
As you progress, you experience a growing sense of accomplishment when designing more complex circuits. The game's structure, where each new component or module builds upon the previous ones, provides a satisfying progression that keeps you engaged and motivated. Many reviewers express a sense of wonder and pride when they successfully design a fully functional CPU, a feat they often attribute to the game's effective teaching of the underlying principles.