Write the prompt around a playable rule
The example offers a column choice, doubling rule and visible overflow boundary. Showing the next block supports planning, while sequential animation reveals how a chain was formed. Keep numbers large enough to read and avoid adding special blocks before ordinary merges behave consistently.
Original concept prompt: “Create a five-column number-drop game. Tap a column to drop a numbered block; touching equal blocks merge into double their value and may trigger another merge. The round ends if any column reaches the top line. Show the next block and animate chain reactions one merge at a time.” This is a recipe for an idea, not a claim that this exact game is already playable.
Play, observe and refine one thing at a time
Drop matching values side by side and in a vertical stack to see whether both trigger the intended rule. Try a placement that causes a two-step chain and follow each result. Check that the top line is visible behind growing columns. If a merge happens in an unexpected direction, state the adjacency order or simplify to one consistent rule.
Tune starting block values, column count or overflow height separately. If players can only react to random drops, make the next piece visible earlier. If the board never feels pressured, reduce space modestly or introduce a choice between a safe low column and a risky chain. Replay the same sequence when comparing revisions.
Do not combine equal values in some directions but not others unless the board explains the rule. Keep the chain result predictable and the danger boundary obvious. A high score is less useful than a run where players understand how placement shaped the next turn.
Playable reference for this prompt: 2048 Drop. Tap one of five columns to drop a number block; equal touching blocks merge and double in chain reactions until a column overflows. Use this example to compare the proposed rules with a game you can try now. For your version, use this check: What needs to be defined about touching blocks?
Questions about number puzzle game prompt
What needs to be defined about touching blocks?
Specify which neighbors count and the order of merges. Diagonal contact and multiple equal neighbors are useful tests for ambiguous rules.
When should column overflow be checked?
Choose whether it happens before or after the resulting chain resolves. Show the top line and test a drop whose immediate overflow would disappear after a merge.