Wasn't sure if I was going to make it but I did!
87 objects destroyed and 5/5 objectives met.
My game is similar where you are destroying objects into pieces. I'm just curious how did you implement it?
My workflow was:
In Blender:
1. Creating the whole object in blender
2. UV mapping it.
3. Creating a duplicate of the model and cutting it into pieces.
In Unity:
Empty GO with a controlling script
whole model is a child.
broken pieces are grouped into a broken gameobject and disabled.
When activated the whole model is disabled and the broken gameobject is enabled.
I had some edge cases but most of my objects were like this.