How to use Gemini to design a falling-block puzzle

The author sujitarou documented developing a Puyo Puyo-style falling-block puzzle with Gemini CLI. The account follows the transition from a vague idea through requirements, design revisions and generated browser-game code.

Gemini first produced requirements for paired falling blocks, connected-color clearing, chain reactions and keyboard or touch input. It then proposed Game, Field and Renderer components. The author did not accept that abstract structure as a complete specification; he supplied detailed questions about state transitions, landing previews and the coordinate-system origin.

Further review separated animation timing from rendering and clarified the connected-cell search, gravity order, score triggers and game-over timing. These decisions became a final implementation plan. Gemini then generated code organized around those components, using DOM rendering and a dedicated score manager.

The source reports a completed playable game, but the public article shortens parts of the code. The evidenced outcome is therefore a documented design-and-generation workflow with representative implementation, not an independently tested release assembled from the excerpt. The account's useful detail is the human checkpoint before coding: ambiguities about state and component responsibility were resolved in the plan rather than left for the agent to guess during implementation.

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Original prompt

Source: note · sujitarou (すじたろう)