Android Puzzle Game with IAP

I’m creating a casual-friendly puzzle experience built solely for Android. The key requirement is a solid in-game economy powered by Google Play Billing so players can purchase hints, extra moves, or cosmetic items directly inside the app. All visual style, level concepts, and monetisation items will be supplied; what I need is the full technical build, polish, and store-ready package.

The gameplay loop should feel snappy on a wide device range (API 23+). An event-driven architecture that makes it easy for me to drop in new stages later is important, even though the first release will ship with a single world. Leaderboards or competitive modes are not part of this first milestone, but your code structure should leave room for them.

Deliverables
• Source project (Unity, Godot, or native Java/Kotlin—choose the engine you’re strongest with and note it up front)
• Release-signed APK/AAB, ready for Google Play upload
• Integrated Google Play Billing (latest version) with test SKUs proving purchase flow end-to-end
• Simple admin document explaining how to add new levels and in-app products

Acceptance criteria
1. App installs and launches without crashes on at least three physical Android devices of differing screen sizes.
2. Core puzzle mechanic works exactly as documented, including victory/defeat states.
3. Test purchase completes, item is delivered, and consumption logic (if non-consumable) is respected on relaunch.
4. Frame rate holds 55+ FPS on a mid-tier device (e.g., Snapdragon 720G) during normal play.
5. Codebase is clean, commented, and builds without errors in the stated IDE/engine version.

With those checkpoints met, the game will be ready for art polish and content expansion.