Starpuffs

Here's an excerpt from Starpuffs' Steam description:

Starpuffs is a cute puzzle game where you solve increasingly challenging puzzles with just one deceptively simple movement mechanic.

You play as Cloudy, a pink ball of fluff who is home to the bright and sleepy Starpuffs. One night, when Cloudy and the Starpuffs are sound asleep, a flurry of wind sweeps the Starpuffs away! You need to rescue them, but it won’t be easy!

• Move Cloudy sideways to split into little Cloudies
• Move up or down to split again into mini Cloudies
• When two Cloudies from the same split meet, they merge together.
• Rescue all your Starpuffs and merge back into big Cloudy in order to give everyone a good night's sleep!