Book of Inferno

Located somewhere in the Underworld, below the earth, lies mythical demons and lakes made solely of lava. This is the setting for the Book of Inferno slot, with the board itself featuring a pile of skulls on either side. Of course, this is accompanied by intense audio features, such as disturbing background music and eerie sound effects when certain symbols appear. Book of Inferno comes with a total of 5 reels, 10 paylines, and a minimum bet size of 0.10 per spin. 

This slot was created by Quickspin, a provider that likes to put its own mark on traditional themes. In the past, they have released popular games such as Azticons Chaos Clusters, Sakura Fortune 2, and Big Bad Wolf Megaways. Quickspin also created Cash Truck, with a festive variation of this title also being available.  

In this title, the standard 9, 10, J, Q, K, and A symbols all make an appearance. They are shown as orange characters, etched in lava against a stone background. Premium symbols include the Commander of Hell, the Lady of Hell, the Lord of Hell, and Anna the Demon Huntress. Should five of these form a matching combination, players will be awarded with 75x, 75x, 160x, or 500x their stake size, respectively. Interestingly, a combination can be formed using only two premium symbols, too.  

There is one special symbol in the Book of Inferno, acting as both the wild and scatter icon. This is represented by a devilish book, which can replace any other symbol as part of a matching combination. It can also trigger the bonus mode, should enough symbols land during the same spin! 

Many people are familiar with the 'Book of' bonus modes, although this slot includes a unique mechanic that can trigger expanding symbols during the base game, too. A random symbol can appear as 'marked' on any spin, and if enough are present, they will expand to fill the reels and award the potential winnings.  

If a book drops, the marked symbol will be upgraded, in order of desirability. For example, king icons can be turned into aces. Should this happen, the upgraded symbols will expand, too, if any more are in view. In the event that the top symbol is selected, 9s will also expand and transform into the most desirable icon. It's worth mentioning that expanded symbols do not need to be adjacent to one another in order to award potential winnings. They can appear on any of the 5 reels.  

The Book of Inferno slot also comes with a free spins mode, which can be triggered if 3, 4, or 5 scatter icons appear simultaneously. This will award players with 10, 15, or 20 spins, respectively, with a 'marked' symbol being selected at the start of the round. Again, if the required number of marked icons appear in any position, they will expand and award players with the associated potential winnings. Additional scatter symbols can upgrade the marked icons for one spin, but the mode cannot be retriggered. 

In conclusion, the Book of Inferno slot offers a fresh spin on the traditional bonus mode. While one symbol is still selected to expand, there is the potential for it to be upgraded on individual spins. The eerie theme is also kept consistent throughout the title.  Play this and other slots at bwin.