If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Your duty is to park the cars safely as they arrive. Get closer to the cars by using arrow keys and get into them by pressing space bar. Then start parking the cars using arrow keys without hitting any objects around you! You need to pick and drive the cars according to the parking slot numbers shown you by the customers coming back with minimum time. Good Luck!
Arrow keys - To drive.
Space bar - Get In/Out of the car.