My name is Asbjørn, I'm the project lead and a programmer for our current game project Astral. One of the parts where I've contributed is the physics we have in Astral, and so, I would like to talk about our physics implementation.
One of the characteristic features we want for Astral is realistic looking physics, although realistic is probably not the correct word for a 2D game. The main point is that we want our game objects to behave similar to the real world counterparts. Our physics simulation is done using the popular Box2D physics engine. Box2D handles simulating the movement of bodies over time and resolves any collisions that occurs, and allows us to handle what happens when a collision occurs or is resloved.Here you can see a video demonstrating the rigid body simulation: