Ask HN: How do I create Android apps with game like elements?

I was playing around with my Starbucks Android app this morning and was playing with the coffee cup component that shows how many stars I have, which shift when I tilt my phone. How can I learn to create this type app component. I keep coming up with game engines but I'm just looking to add 2d physics engine type interactivity to existing apps that are not games. Where should I start?