Yay, I beat level 28! Its 1 AM! SPOILER/WALKTHROUGH:
You have to attach the white ball to the wooden platform at a point roughly between the hinge and the spot where the black ball will hit the platform. The white balls should balance the platform enough for the black balls to hit the middle fish, then the platforms should flip around to hit the other two fish. + if this helps! :)
I think that we should be able to fight bosses again in another small area if we want to scan missed minions or just fight them for fun. All those who agree with me, please plus this.