Focus on the first image. See the solid blue square? It must land on the big blue square. How to do so? First, the red cube must roll down to the bottom layer and land on the small red square. That will bring the red & white cube, which is an elevator, down. Next, get the blue square to roll on top of the now-down red elevator. Move the red cube off the elevator activator. And that will make the blue cube rise up to that level. Then, the blue cube must activate its elevator to get the red cube back upstairs.
There are 80 levels and I've done approximately 55 of them. Tough! The game costs $.99 which will provide you with a bunch of hours entertainment.
A very similar game is QVOID, which I reviewed almost 4 years ago.