The player's primary logic operates within the known possibilities of physics. Keep in mind gravity, weight, mass, density, force, buoyancy, elasticity, etc. Use this as the starting point, but do not be limited by it.
An understanding of motion and the driving forces thereof is crucial in understanding games. Most objects in games move. That is what makes them dynamic. Whether it be a 2D character such as the original Mario or a fully fledged 3D character such as Halo's Master Chief, they and their game environments are in constant motion.
To grasp the concept of motion, especially ...