Thorough slot game reviews require going far beyond the audio and visuals aspect of the release. The graphics, music, and sound section you read in our Book of Inferno slot review was just a warm-up for the more important things.
Our review will reveal some crucial features that can help you understand what you can get from this game and how to play. These include the slot's theme, stake range, reels and paylines, special features, and more.
Like always, we will continue with the theme.
Theme – Demons
It's not easy to choose just one word to describe the theme of the Book of Inferno slot because it features a more complex story than usual.
First, players will find a character that appears in several Quickspin slots. Anna, which is usually in the role of an explorer, acts as a demon hunter now. Her job is to enter the underworld and defeat the three demons before they can gather their armies and attack our world.
Experienced players know they should head to the paytable to learn about the slot's story. This time, we have a paytable with ten regular symbols: six playing card values made of metal and four characters – Commander of Hell, Lady of Hell, Lord of Hell, and Anna the Demon Huntress.
All the regular icons can be marked on any spin (Marked Symbols). Also, the Book is both a Wild and a Scatter symbol.
Reels
If it works, don't change it. That's probably the motto of the creators of the Book of Inferno slot, at least regarding the number of reels. So, you can expect 5 reels and 3 rows per reel in this game. The 5x3 gameboard is typical for modern slots.

Paylines
Ten – that's the number of paylines you can expect in the Book of Inferno online slot. Players can't change this number, nor does the game alter these paylines when users activate bonus features.
The low-paying regular icons pay for three to five matching symbols on a payline. In contrast, the high-paying ones promise rewards for two to five of the same kind on a single payline.

RTP
Next on the list of the vital game feature of the Book of Inferno slot game is the theoretical payout rate, also known as RTP (Return to Player). Based on the simulation conducted by Quickspin's team, the default Book of Inferno RTP is 96.15%.
You shouldn't take this value for granted because it's just a recommended/default percentage provided by Quickspin, meaning online casinos can change it if they want to. In fact, some of them have already done this, and you can tell that by looking at the table below.
In addition to the RTPs related to Book of Inferno found in various top-rated casinos, we also provide reviews with information like description and evaluation of the game library, banking solutions, customer care, mobile-friendliness, and welcome bonuses and deals. Reading these reviews before signing up at an online casino is very helpful.
Also, UK players looking for the best places to enjoy slots should visit our page featuring our recommended slot sites.
Stake Range
Regarding the game's stake range, we will mention the coins button, which reveals a selection of 16 stakes once you click on it. We like how this release enables players to play with low bets (£0.1) and high bets (£100).
Max Win
You shouldn't expect something spectacular from the max win limit of the Book of Inferno slot, but it's fair to note that this is an average value. The max payout is capped at 5,846x the player's bet.
Marked Symbols
In addition to the ordinary versions of the regular symbols, players can land their Marked versions. These Marked symbols can land on any spin randomly. When they do, if there are enough of these icons to form a winning combo (three, or in the case of high-paying regular icons - two or more symbols), the Marked icons will expand to fill the reels where they appear.
In addition, they pay anywhere on a payline. In a way, they act like Scatter symbols, but they still have to be on the same payline, not on consecutive reels starting with the first.
On the other hand, we have the Book serving as a Wild icon substituting for missing regular symbols. When a Book is part of a winning combo with Marked signs, it will upgrade that icon for a chance to get more Marked icons and expansions on the reels.
Interestingly, when a Marked icon goes over the highest symbol, the lowest-paying icon will be turned into the highest-paying one.

Free Spins
The second unique feature here is the free spins. We noted that the Book plays a dual role here and acts as a Scatter symbol. So, when players hit three, four, or five Books anywhere on the grid, they will start 10, 15, or 25 free spins, respectively.
You can win extra spins in this round by landing three to five Books, and you should expect the same number of free spins. Another great thing about this round is that one of the regular symbols will become Marked at the beginning of this special feature providing more winning chances to players.
Jackpot
The Book of Inferno slot has two unique features. Still, it doesn't offer a direct jackpot prize. As a reminder, we will mention that the highest reward you can win here is capped at 5,846 times your bet.
OLBG has a page with some of the best jackpot slot games for those who want to try titles like that.

Play Experience & First Impressions
Whenever you start a gaming session with a big win, you know that you can relax and unwind. That's how my 100-spin test of the Book of Inferno slot game started. Namely, after just four spins, I launched the Marked Symbols feature and won 31 times my total stake (combos with many expanded Aces).
I should mention that this feature was activated five times during the test spins. Just two of these rounds, including the one discussed above, brought something in return (the other helped me win 5 times the total stake).
Also, I was far from activating a round of free spins, although I hit two Books in a single round. Regarding the base game, the number of wins was a bit low, which is normal for high-volatility releases like the Book of Inferno online slot.
These base game wins were worth between 0.5 and 3 times by bet. When the slot summed up everything at the end of the 100-spin test, I had an RTP of 57.5%.
Finally, I will mention the audiovisuals here. The music was surprisingly refreshing, and the artwork was outstanding. This is especially true for the animated sequences featuring the book emerging from the pentagram when the Marked Symbols feature is activated.