Sites like these often have multiple "Download" buttons. The real one is usually smaller or hidden behind a text link. Avoid buttons that look like flashy advertisements.
If you are downloading games from sites like the one mentioned, keep these safety practices in mind:
You start with a basic car. Use the money earned from each run to upgrade your fuel tank first, as running out of gas is the most common way to fail.
Don't just drive; use your mounted weapons to clear obstacles and zombies that might slow you down. Conserve ammo for large groups or heavy obstacles.