Design for touch and small screens
For a game designer, this purchase recovery prototype should make every player action and clearly displayed outcome easy to evaluate. Write how to handle reloads, interrupted delivery, duplicate clicks, and insufficient Koin without double granting. Choose the offer moment, explain the game benefit, and protect the complete free path. Compare the experience before and after ownership. 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.
Judge the offer in the core loop
Run the game without opening the purchase choice, then run it with the item. Compare pacing, motivation, difficulty, and recovery so the offer supports play instead of repairing frustration that was added deliberately.
Make the player promise concrete
Describe what changes on screen, how long it lasts, where it appears, and what remains available without it. Replace value labels such as better or premium with rules a player can observe.
Review the moment of choice
Check what the player was doing immediately before the offer and where cancel returns them. The item should arrive after enough context to understand it, but never during a time-critical or emotionally pressured action.
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.