If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You need to identify the difference and click on it to get points. For every correct click 50 points will add up with your scoreboard, remember that your score will reduce for every wrong click and also game gets over at the end of third wrong click. You have 3 lives to play this game. Complete all interesting levels and enjoy the game. Have fun.
use mouse to interact