A prototype earns its value by changing what a team knows. It should expose the assumptions most likely to become expensive once production is moving at full speed.
Start with the decision
Before choosing tools or deciding how polished a prototype should be, name the decision it needs to support. Are players finding the core interaction satisfying? Can the feature perform within the target hardware budget? Does the idea still work when ten players use it at once?
A precise question keeps the prototype small. It also makes the result easier to evaluate because the team agrees on what evidence matters before the work begins.
Build only enough reality
High fidelity is useful when visual response, timing, or presentation is the uncertainty. In other cases, polish can hide the very problem a team needs to see. Temporary art, simplified data, and narrow test environments are often the fastest route to an honest answer.
The goal is not disposable work for its own sake. The goal is to avoid building a production-ready solution before proving that it is the right solution.
Turn the answer into production direction
A successful prototype should leave behind more than a demo. Document the constraints it revealed, the measurements that mattered, and the decisions the team made. That context gives design, art, engineering, and production a shared starting point for the next phase.