Basically, it is a series of puzzles that requires you to throw balls at various constructions or to carefully pull those constructions apart. Some are easy while others are quite tricky to solve. But you can come back to the game and progress in as short or as long steps as you like. Actually, during one long session my throwing arm hurt considerably afterwards. I call that 'exercise.'
You can play with the kids in a cooperative mode too but really, why let them have a go when they can just watch and shout at your poor choices?