If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You have 60 seconds for each picture. If time runs out you lose the game. Also you can get 1000 points for each picture if you find the five differences, but if you mistake and click on wrong place you lose point. If you are ready to get your score, grab your mouse and start!
Use mouse to click when you finds some difference. If you click away from the correct place will receive negative points.