Book of the Cleo

The Special Expanding Symbol is one of the most iconic and popular mechanisms in online slot history, a core free spins feature primarily found in 'Book of...' series games. The essence of this feature is that one regular symbol, randomly selected at the start of the free spins, gains a special power. This symbol, as long as it appears on the reels in the required number to form a win, will expand to cover its entire reel and create massive wins regardless of its position.

Hold and Respin, or 'Hold & Win', is one of the most popular core bonus game mechanics in modern slots. The essence of this feature, unlike traditional free spins, is to 'Hold' bonus symbols on the reels and 'Respin' the remaining empty spaces to fill up the screen. This system was popularized worldwide through 'Money Train 2's' 'Money Cart Bonus' and is the foundation for numerous developer-specific brand features like Wazdan's 'Hold the Jackpot™' and Playtech's 'Fire Blaze™'.