"Combining power-ups increases their effect and lets you clear the filed more efficiently! If you see power-ups located on adjacent tiles, simply drag one onto another. Сombined, they function as follows:

Combining Bomb with another Bomb increases the radius of the bomb explosion by two tiles.

Combining Bomb with Rocket removes three rows and three columns of pieces coherently.

Two Rockets combined function just like Broom, removing one row and one column of tiles.

Combining Bomb or Rocket with a Helicopter makes the Helicopter take the Bomb or Rocket to a tile with a level goal on it.

Two Helicopters combined produce three Helicopters that target the level goals.

Fireworks combined with Rocket, Bomb or Helicopter turn all the pieces of one type (ones that are majority on the field) into respective power-ups.

Two Fireworks combined remove all pieces from the field, weakening the obstacles that require several steps to be destroyed."