Use simulated value only
For a technical producer, this purchase recovery prototype should make every player action and result the player can inspect easy to evaluate. Write how to handle reloads, interrupted delivery, duplicate clicks, and insufficient Koin without double granting. Map preview, confirmation, a player cancellation, not enough Koin, pending, success, delivery, owned, and reload. Give every failure a safe next action. Treat Koin as a classroom game variable and do not request payment details, account credentials, or personal student information. The exercise is about interface states and responsible design.
Make the learning objective visible
Ask students to explain the item promise, free path, cancel behavior, failure recovery, and production boundary. Grade reasoning and playtest evidence rather than purchase completion.
Plan instructor-led testing
Run the prototype on shared devices with accessible controls and privacy-safe displays. Native billing, identity, durable storage, refunds, platform approval, and real transactions remain outside the lab.
Name every state and owner
Separate preview, confirmation, pending, success, delivery, owned, insufficient Koin, cancel, interrupted, and reopened states. Assign later production work for identity, persistence, native billing, security, refunds, policy, and monitoring.
Define idempotent recovery
Repeated confirmation, a slow response, navigation during delivery, and reopening must resolve to one result. Record which state is authoritative and how the player can safely retry without another grant or Koin deduction.
Turn the prototype into tickets
Capture the visible behavior first, then create implementation tasks with expected examples for each transition and platform boundary. Do not translate a working browser interaction into an unsupported claim that backend commerce is complete.
Keep pending understandable
If delivery is interrupted, explain whether the result is pending, safe to retry, or already complete. Do not show both failure and success. Test that behavior using classroom game labs. Use simulated Koin values and instructor review; do not collect student payment data.
Make retry idempotent
Repeated clicks and reloads should resolve to one purchase result. The player must never receive duplicate items or lose Koin twice. Test that behavior using classroom game labs. Use simulated Koin values and instructor review; do not collect student payment data.
Return to a safe game state
A cancelled choice, a Koin shortage, and recoverable errors should preserve progress and offer a clear return or retry action. Test that behavior using classroom game labs. Use simulated Koin values and instructor review; do not collect student payment data.