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Book of Secrets Extra Slot - Review, Free & Demo Play

Book of Secrets Extra
Book of Secrets Extra
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Updated: 22.07.2025
Reviewed by: Ella Houghton
The Synot Games vendor knows how to make engaging games, even when the theme seems to be classic and common. Oh yes, this time, the Book of Secrets Extra slot released on 12/11/2022 is going to make the gambling experience of Slotsjudge visitors mystical and full of adventures. Let’s visit the ancient Egyptian temple through this review not to miss its precious souvenirs on the 5 reels and special features like Free Spins, Gamble, and even Bonus Buy. So, have you prepared your desktop or mobile gadget to get started?

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In this review
  1. Slot details
  2. Theme
  3. Bonus Rounds & Free Spins
  4. Summary
  5. Where to play
General information about Book of Secrets Extra slot

General information about Book of Secrets Extra slot

Rating by Ella Houghton:
7.9
User’s Rating: Not rated yet
SYNOT Games
Write a review +25 SJ points
  • Release Date:
    12.11.2022
  • Volatility:
    High
  • RTP:
    96.1%
  • Multiplier:
    No
  • Max. win:
    500x
  • Bonus game:
    No
  • Free spins:
    Yes
  • Scatter Symbol:
    Yes
  • Wild symbol:
    Yes
  • Symbol Stacked:
    No
  • Jackpot Game:
    No
  • Slot lines:
    10
  • Slot reels:
    5
  • Layout:
    5-3
  • Stakes range (€/£/$):
    0.10 to 20
  • Slot Theme:
    Ancient civilizations
  • Technology:
    JS, HTML5
More infoLess info

Licensed and tested by

  • Gambling Comission
  • Gaming comission
  • HGC (Hellenic Gaming Comission)
  • MGA
  • ONJN
  • Spel inspectionen

How to Play

Book of Secrets Extra is a slot with simple rules and mechanics. It has a 5x3 scheme, 10 paylines, and several bonus features we’ll describe below. It won’t be hard to get started due to the Slotsjudge rating and guide over here. These are the steps to let you master this Egyptian-themed machine:

  1. Compare online casinos from our rating and choose the one to sign up
  2. Launch Book of Secrets Extra on the device you find convenient (PC or mobile)
  3. As the paylines are fixed, you regulate the bet (€0.10–€20 per spin)
  4. Then, the golden button on the right invites you to get started

Book of Secrets Extra RTP and Volatility

8.1 
The journey to the ancient land isn’t that risky when the slot has a good RTP of 96.07% and medium-high volatility, right?
We like it when providers take care not only of basic things like interface and features but also of payout qualities to let gamblers fully enjoy the game. In the case of Book of Secrets Extra, Synot Games pleased us with its high RTP level, while the volatility allows players to hunt for nice rewards yet avoid high risks. By the way, the hit rate here is 30.95%.

Theme

9 

Perhaps, you remember those engaging horror movies about the mummy or historical films dedicated to archeologists in Egypt. All these things are displayed on the screen once you open Book of Secrets Extra. You will enjoy the sound effects and the music played when the slot is launched. We think that it’s a great way to add some new vibes to the popular Egyptian theme gamblers love.

According to the slot’s theme, it’s quite expected that its symbols will be corresponding. When we are talking about card suits, they slightly vary, so you get 0.5x to 10x for 3 to 5 10–Q cards, while K and A pay up to 15x. However, it’s better to focus on more profitable symbols, including the ankh and scarab paying up to 75x. The pharaoh has a value of up to 200x. And the lucky archeologist pays up to 500x.

By the way, the golden book that launches free spins can pay up to 200x. It has both a Scatter and a Wild.

Theme
Book of secrets extra slot paytable

Mobile Compatibility

Book of secrets extra slot mobile
One more thing Synot Games does perfectly is delivering HTML5-friendly games to let players access the software on all devices they have. Do you like gambling on your phone on Android? Or, maybe, your iPad? At any rate, Book of Secrets Extra is fully mobile-optimized, so you are welcome!

About Synot Games

Known as a team of gambling enthusiasts, Synot Games has been working on different solutions for online casinos for 30+ years. Statistically, the company has developed 90+ games, has 140+ experts, operates in 30+ countries, and, of course, has drunk 526+ liters of coffee per month. The vendor holds MGA, UKGC, ONJN, and other licenses.

The slots are mobile-optimized, RNG-tested, and very engaging. And here are the other games from SYNOT Games not to miss: Respin Joker 243, Skull Bonanza, Zeus Wild Thunder, and Monkey Slots.

Bonus Rounds & Free Spins

8.5 

Free Spins

Virtual archeologists are happy to find not ancient items but golden books on the screen since they launch free spins gamblers like so much. For 3+ Scatters, you get 10 free spins that are played with a special symbol. Besides, the feature can be retriggered with an extra symbol being chosen for expansion. It’s activated when the symbol is involved in a winning position.
Book of secrets extra slot Free Spins

Gamble Feature

The feature can be launched in the base game each time you have a winning combination. Moreover, the wins from free spins can also be involved. When you want to gamble, find the widget with cards on the right. The round is opened and you need to guess the card’s color to multiply the winning by 2x. Additionally, the round has a ‘Halve’ button to let you gamble with only half of the amount you win. The round can be played 10 times in a row.

Bonus Buy

On the left, players find a cart which is a Bonus Buy widget. It allows you to buy free spins and regulate the bet (€2 is the maximum) for the bonus feature. You pay 100x the bet, so, for example, a bonus round with 10 free spins at €2 per spin will cost €200.

Book of Secrets Extra Demo Play

We can’t say that Book of Secrets Extra is a very risky slot. However, why not save your money and test it for free for a while? SYNOT Games has a perfect demo version of the game, and you find it right here. Use free coins and make your Egyptian adventure completely riskless!

Max Win

6 
Perhaps, 500x isn’t the highest max win out there, but it’s perfect for a classic slot.
Yes, you may have met slots with multipliers overcoming 10,000x, and Book of Secrets Extra is not the case. But it’s worth noting that both volatility and chances to win are huge when we are talking about those games, while Synot Games made this machine less risky and more affordable, so the 500x reward for your adventures is a nice goal.

Overall Rating

7.9
Do we like Book of Secrets Extra? We definitely do, and you will also like it. Getting 10 free spins with expanding symbols is great. And when you add a re-trigger opportunity and features like Bonus Buy and Gamble to this blend, the overall experience becomes even more attractive. Plus, the Synot Games’ reputation and the mobile optimization of the slot, for sure, make us recommend it!
Hits
Scatters activate 10 FS with expanding symbols
Free spins can be retriggered
You can buy the bonus game
Gamble feature has a ‘Halve’ option
Misses
The max bet during Bonus Buy is €2

Book of Secrets Extra Slot - FAQ

Does the Book of Secrets Extra slot have engaging bonuses?

Yes, we liked the 10 free spins with a special expanding symbol, as well as the gamble round and Bonus Buy.

What are the other popular slots from Synot Games?

They are Respin Joker 243, Skull Bonanza, Zeus Wild Thunder, and other slots you find overviewed here at Slotsjudge.

How much money do I need to play Book of Secrets Extra?

The bet per spin is €0.10–€20. However, when we are talking about the free version you find on this page, you don’t need to pay money at all.

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Ella Houghton
Ella Houghton
Expert in: News, Blog, Slot reviews, Payments
Ella is a professional content-writer with 8 years of experience in the casino sphere. She has broad knowledge of gambling related themes and is happy to share this with Slotsjudge.

2126 articles

Reviewed by Editor-in-Chief
Nikita Lukanenoks

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