As in the first game, the three key symbols in Highway Kings Pro are trucks. Once again, the red truck is Mack Daddy, paying 10 to 2, 50 to 3,500 to 4 and 10,000 for the highest prize of 5. The other two yellow and green trucks can be mixed and matched to form a winning combination. They pay 5 to 2, 20 to 3, 150 to 4 and 1,000 to 5.
The bonus symbol is indicated by a checkered flag. It only appears on the first and fifth reels, and if it falls on both, it activates the truck racing reward. A screen with three trucks will appear, each representing a series of free games. Claim 10 to 25 free spins by clicking on the corresponding arrow to select one of the vehicles. After that, the screen will change to show three highways. Decide which game you want your truck to play in and watch the action. Depending on where your truck enters, you will get a free game multiplier between 2 and 5.