Source: Official screenshot
Analysis
The rocks and gold nuggets don't have any physics-based audio.
Enemy Materials - I think it's absolutely brilliant how the enemies are composed of a behaviour and a chuck of diggable material. Like the first boss, which is a golden skeleton with rock around it. Punch the rock, and the skeleton will be exposed. Later on, we have drones that fling chunks of rock at you. Or the diggers, which can build rock towers or be made out of spiky plants.
Story Summary
The Odd Rock is actually Pauline, Mario's girlfriend from the original Donkey Kong.