I do not know how to rate this level. I heard “click” and the check mark appeared but winning was no more than a shot in the dark. If the normal moves lead to nothing, something else must be required. That something is a bit weird. Edit: after having played the level a couple of times, the solution appears more logical than I initially thought. My initial solution was a matter of luck.
This is a hard one to rate ... so think of this as a rounded-up 3.5 ... Spoiler There can only be one thing to do since the win isn't visible and there's clearly no way for B to get into the interior. But it's enough fun to work the first ball into the well under the lift. I actually ended up winning without using the rotating arm, but I can see how it might be needed if the second ball hangs up in the tower.
@DrunkApple - That's two unstable levels in a row. Since the balls were on flat surfaces, the odds were very high that they would stop and force a restart which they both did. Poor design shouldn't be used to make a level more challenging.
So, where is the win?? I have got... Spoiler [A ball in the hole at the bottom of one tower, the lower ball pushed into it's tower, B dropped down into the hollow tower....... But nothing has triggered the win and if don't know where it is I can't see what else to try??]
@gmacpro lower ball can be pushed with back to B if it gets stuck in the tower. The First ball shouldn't be that much problem because it's in the very start, and it can be pushed with the slider lift.