Use simulated value only
For a game designer, this catalog design prototype should make every player action and player-visible outcome easy to evaluate. Write how to define item identity, value, Koin price, preview, and ownership before checkout. Choose the offer moment, explain the game benefit, and protect the complete free path. Compare the experience before and after ownership. 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.
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.
Compare items consistently
Use the same fields for every offer: preview, benefit, ownership or duration, specific Koin amount, 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.