The most popular slot machines types you will find online are ones that have a bonus or bonus game you can play if you hit certain symbols during a regular spin.
The most common bonus you will find is the free spin, which is in more then half of all video slot machines. When you get a certain combination of a special symbol on the playing field you will win several free spins. These spins are automatic and spun by the machine. Once all the free spins have come to the end everything you won is added to your winnings.
Other bonuses include the cascade feature where wins are removed and further symbols fall into their place causing a chain reaction of multiple wins. Another is expanding wilds where the wild symbol extend out to fill a entire reel. You will also find slots with wild multipliers that act as both a wild card and multiply your winnings at the same time.
Wheel of fortune slot games, as well as wheel of wealth slot machines based on TV show, are quite popular at modern online casinos. Playing this type of slot machines you have a chance to enter Wheel of Fortune game screen and win big prizes.
One of the more fun bonus to play are games. When you win a bonus game you will come to another screen that has a game for you to play to win extra coins and bonuses. Some versions of the game you pick one item and you win that item and the bonus round is over. A different version you can keep picking items until you hit a certain item that ends the bonus round. Multilevel games you can move on to more bonus screens if you hit a certain item in the previous bonus round.