If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Hit all the coloured hearts with the bow and arrow given to you and fill the heart loader within the given time limit and go through all the levels. Avoid hitting the black hearts for it will take away one of your life. Change the color of the arrow according to the color of the falling hearts. If the color of the heart and arrow gets mismatched, then your score gets reduced.
Click and drag the arrow to aim and shoot. Press the following numbers to change the color of the arrow.