You will defeat Minion Pigs if two sets of balloons are popped near them.
Gold Coins
Gold coins are the premium currency of the game and are rarely earned, they tend to be given as special gifts or rewards, like logging in to Facebook. Gold coins can be used to buy purchasable power-ups and continues upon losing a level.
Nearly Everything Floats Up
In Angry Birds Blast nearly everything floats up unlike the Candy Crush and Bejeweled games where tiles fall down onto the board from above. The only things that don't float up even if an empty space appears above them are non-balloon objects such as Piggies, their forts, and cages.
Rocket Power-Up
Remember when you earn a Rocket power-up that it changes direction each turn so if it is facing the wrong direction just move something else so that hopefully on your next turn the Rocket power-up has moved so it is facing the correct direction allowing you to either clear a row or a column.