Plumatch is a fun and fast-paced casual game. It's all about tapping the right things at the right time. Tap the wrong things too often, and you'll lose.
These are the good ones, you want to get them all. Let'em escape and you'll lose a heart. Tap'em when they are in the target area and you'll score. The better your timing is on tapping them, the better your score will be. See the ingame tutorial for more information on the scoring system.
These are the bad ones, you should better avoid them unless you want to lose your hearts quickly. Just ignore them and you're good to go.
What? You didn't ignore a bomb, let a star escape or tapped at the wrong time so you lost a heart? Then better collect the bonus hearts to stay alive longer. But they are rare, so I would get any I can see if I were you.
Get the highest score possible. And then try to beat it again, and again, and again, and...if that's too boring for you, there is a leaderboard as well, so you can compete with other players from around the world and try to beat their scores! Have fun and good luck!