When looking to trigger the Bonus Game in Zombie Circus online slot machine, you'll need to keep an eye out for the Bonus Symbol. Luckily, it is easy to spot because it looks like a neon glowing carousel with electric horses spinning around it.
From here, you will need to find out which number of Zombie Waves you will receive. This will be determined by the number of Bonus Symbols you land. For example, three Bonus Symbols will trigger two Zombie Waves. Four Bonus Symbols will trigger three Zombie Waves, and five Bonus Symbols will trigger four Zombie Waves within the Bonus Game. The latter is the maximum number of Zombie Waves that are available at any one time. After this, you will need to select one of the five zombies on the screen. Then, once you have picked one of these characters, you will unearth a prize that will come into its own at the beginning of the Free Spins Feature.