Protect rendering performance
For a game designer, this inventory delivery prototype should make every player action and result the player can inspect easy to evaluate. Write how to connect successful purchase to a visible owned or quantity state. Choose the offer moment, explain the game benefit, and protect the complete free path. Compare the experience before and after ownership. Open and close the interface during GPU-heavy scenes, then monitor input, frame pacing, and canvas recovery. A commerce overlay should not leave the game loop paused or controls captured unexpectedly.
Coordinate DOM and canvas state
Make the selected item and outcome visible in both interface and gameplay context. Handle focus loss, pointer lock, fullscreen transitions, and a resized canvas around confirmation and return.
Exercise context recovery
Simulate refresh, background suspension, and a lost rendering context. The player-facing purchase result should reconcile separately from graphics recovery and must never duplicate an item.
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.
Connect success to the item
A success message is not delivery. Place the cosmetic, consumable, unlock, or upgrade in the screen where the player expects to use it. Test that behavior using WebGL games. WebGL rendering and commerce state need separate failure testing.
Show ownership and quantity
Use owned, equipped, unlocked, or remaining quantity as appropriate. The state should match the promise made on the offer card. Test that behavior using WebGL games. WebGL rendering and commerce state need separate failure testing.
Verify delivery after reload
Reload the prototype and return to inventory. The item should remain visible without subtracting Koin or granting a second copy. Test that behavior using WebGL games. WebGL rendering and commerce state need separate failure testing.