Use simulated value only
For a technical producer, this catalog design prototype should make every player action and clearly displayed outcome easy to evaluate. Write how to define item identity, value, Koin price, preview, and ownership before checkout. Map preview, confirmation, cancellation, too little 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.
Compare items consistently
Use the same fields for every offer: preview, benefit, ownership or duration, full price in Koin, and owned state. Consistent cards make differences easier to understand. Test that behavior using classroom game labs. Use simulated Koin values and instructor review; do not collect student payment data.
Keep the first catalog small
Start with one to three clearly different items. A large grid makes it harder to find unclear value, duplicated promises, and missing delivery states. Test that behavior using classroom game labs. Use simulated Koin values and instructor review; do not collect student payment data.
Design owned and unavailable states
A catalog also needs sold, owned, equipped, and unavailable presentations. Do not leave a purchased item looking buyable after reload. Test that behavior using classroom game labs. Use simulated Koin values and instructor review; do not collect student payment data.