You get power-ups in match-3 levels every time you match four or more pieces. Here are the power-ups currently available in the game:
Firecrackers remove everything within a one-tile radius. You get them by matching four pieces of the same color.
Bombs remove everything within a two-tile radius. You get them by matching five pieces of the same color.
Dynamite removes everything within a three-tile radius. You get it by matching six pieces of the same color.
Warheads remove everything within a four-tile radius. You get them by matching seven or more pieces.
Lightning removes all the pieces of the same color from the field. You get it once it is charged, and you can do that by activating the other power-ups.
Energy Blasts clear three rows or three columns of tiles. You can get Energy Blasts once they are charged, and you can do that by activating the other power-ups.