Look then Act

Thanks to @Don G Rowe who found a back door, I've reposted the level with that fixed.

Spoiler: Hint

A Belly Bump will help descend B - Stand in front of a slider, raise and lower slider, the right rhythm will cause a bump.

Sorry, but this one just became too tiresome. Belly bump is too random and inconsistent.

@Don G Rowe - Okay you tried and commented so that's appreciated. As for the belly bump, it works 100% of the time for me so maybe my B's belly is bigger. It takes about 3 to 4 bumps before the fall.

Spoiler

Found a more consistent technique to make B drop down the first time. Pretty straightforward from there, but the second drop can also produce some erratic behavior, and it's decreasingly fun to have to keep restarting. Fortunately the ground level does provide some recovery points.

@Don G Rowe - Thanks for rating. The name does warn to look before you act.

As suggested by my comment on No R Left Behind, I find the Belly Bump trick very useful even with a horizontal slider

I solved this clever level, though, for its puzzling layout, I'm not sure if I solved it correctly.

Spoiler

I used only three balls

@tebkanlo - For the intended way, two balls are required at the top and 2 balls at the bottom so you do have one spare ball. Glad you won, thanks for the comments and the rating.