Rule sets and physics are not the same thing. While I don't find the rule sets shallow for many of the Zen games, I don't see any value in trying to make the statement that the ramp shots would be impossible. The point being, its a video game, not the real thing, so it doesn't matter.
Flippers are your primary interface to a pinball game, real or otherwise. So when I play a virtual representation, this is what I focus on more than anything. As someone that has spent hours practicing live catches, flipper passes, dead catch, bounce etc, flipper accuracy and physics is my primary trait for focusing on when reviewing a game. As such, when I discuss the physics of a game, I am focusing 90% on the accuracy of the flippers, and how the flippers react with the ball. And when comparing PA to Zen, there is just no comparison, Zen blows PA out of the water.