Combining power-ups helps you clear more pieces and produce bigger explosions. Here are the combinations currently available in the game:
Bomb+Bomb—this combo doubles the radius of the bomb effect.
Rocket+Bomb—removes three rows and columns of pieces.
Rocket+Rocket—removes one row and one column of pieces regardless of which way the Rockets are pointed.
Propeller+Bomb or Rocket—the Propeller turns all pieces of the same color into Bombs or Rockets. For example, yellow Propeller+Bomb turns all yellow pieces into Bombs.
Propeller+Propeller—removes all pieces from the field, clearing one obstacle layer in the process.