If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Helicopters will deliver new arrivals to the waiting house. Transport the animals to their own pens by clicking on them, then tend to their needs: Health, Cleanliness, Happiness, and Food. When an animal's been tended to, a helicopter will transport it to its new permanent home. Patch up the number of animals shown in the top right to complete a level. If an animal dies, it will take 20 seconds off the timer.
This game is played with mouse only.