At the start of every level, you can choose boosters to help you complete the level.

The booster options are:

• Bombs - a bomb is placed randomly at the start of the level.
• +3 Moves - increase the total number of moves available to complete the level by three.
• Rockets - a rocket is placed randomly at the start of the level. 

Silver coins can purchase these boosters at the start of a level. Just tap the boosters you want to use on the pre-level screen so that a green checkmark appears next to it, and the booster will be available for that level!