To complete levels more effectively, you may use special boosters. These can be obtained as a reward, or purchased in the respective section of the game store.
Besides, you can get boosters for completing quests of the Kitten Rescue event.

There are the following boosters in the game:
Hammer — removes a selected piece and a tile under it.

Bomb — removes one selected piece and four pieces around it.

Lightning — removes a horizontal row of pieces.

Megabooster — removes all the pieces of the chosen color. To get this booster you first have to charge it by making matches and using other boosters. Use Megabooster wisely, it can be of great help in completing a level