Design for touch and small screens
For a technical producer, this purchase recovery prototype should make every player action and player-visible outcome easy to evaluate. Write how to handle reloads, interrupted delivery, duplicate clicks, and insufficient Koin without double granting. Map preview, confirmation, cancelling the action, an insufficient balance, pending, success, delivery, owned, and reload. Give every failure a safe next action. Use comfortably separated confirm and cancel controls, readable Koin amounts, and a layout that survives portrait, landscape, browser chrome, and an on-screen keyboard without hiding the item.
Expect interruption
Simulate locking the phone, changing tabs, receiving a call, and returning with a slow connection. The player should see one understandable result and retain a safe route back to play.
State the platform limit
A mobile browser prototype is not an App Store or Google Play binary. Native billing APIs, device identity, refunds, entitlements, and submission need separate implementation and review.
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 mobile web games. Mobile web is not the same as an App Store or Google Play binary.
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 mobile web games. Mobile web is not the same as an App Store or Google Play binary.
Return to a safe game state
Cancelling the action, a Koin shortage, and recoverable errors should preserve progress and offer a clear return or retry action. Test that behavior using mobile web games. Mobile web is not the same as an App Store or Google Play binary.