This option is a surprise...

To catch the surprise, water it with a few drops.

The stopwatch adds time when water hits it.

This option can be useful to complete some levels.

To catch the Bars bonus, water it with a few drops.

To catch the Bombs bonus, water it with a few drops.

To catch the Bricks bonus, water it with a few drops.

When you hit this obstacle, you have to wait for the water to reach a certain height.

Once the water reaches that level, the cork falls to the bottom and lets the water flow.

The start and finish points for the water drops are indicated by arrows before starting a level.

Teleports are passageways for water drops to reach a specific point. They can take on the shape of the containers. It's up to you to find them...