Book of Fusion Slot Review

Expert Rating: 3.5 out of 5
Review by Chris Taylor
Last update 21st June 2022
Review by Chris Taylor
Last update 21st June 2022

Head to Nikola Tesla’s lab in the Book of Fusion slot from WMS/Light & Wonder. With 5 reels and 10 paylines, the gameplay centres around the Free Spins Bonus feature. Here, you begin with 10 free spins plus 2 special expanding symbols. Each time you retrigger the feature, you’ll win 10 additional free spins and 2 more special expanding symbols. This can lead to 50 free spins and 10 special expanding symbols. With a 95.97% RTP rate and 6,519 x bet max wins, let sparks fly in our Book of Fusion review.

Book of Fusion Max Win
6,519 x bet
Light & Wonder
Type of Slot
Video Slot
Stakes Range
10p to £35
Bonus Features
Yes (2)
Free Spins/Multiplier
Max Win
6,519 x
Medium to High

Book of Fusion Slot RTP, Details & Wager Limits

Reels/Paylines: 5 reels + 10 paylines

Stakes Range: 10p to £35 per spin

RTP: 95.97%

Max Win: 6,519 x bet per spin

The Book of Fusion slot is played on 5 reels, 3 rows and 10 fixed paylines. Winning combinations must occur on consecutive reels, beginning with reel 1. You will need 3 or more matching symbols across any of the 10 paylines. There is a 33.11% hit frequency rate which means a win will occur every 3.02 spins on average.

Stakes range from 10p to £35 per spin. Click on the ‘Coins’ icon which will allows you to change your bet using the plus and minus buttons. For non-UK slot players, there’s an Autoplay function where up to 100 autospins with single win and loss limits can be implemented.

The Book of Fusion RTP is 95.97%. This is just about average for an online slot (norm is 96%). The volatility is in the medium to high category with the majority of bigger wins coming from the free spins.

The maximum win is 6,519 x your total bet per spin. This is more like to come in the free spins due to the expanding symbols. The average win in the feature is 63.6 x bet with a 1,000 x bet win or higher occurring every 603,136 spins on average.

Theme – let sparks fly

Theme: Science

High Value Symbol: Scientist

Compatibility: Mobile, Tablet, Desktop


With a science theme, the Book of Fusion slot takes you inside a scientist’s lab where sparks fly. Based on Nikola Tesla, the inventor, engineer and futurist is famous for inventing the Tesla Coil. The system transmits electricity wirelessly and this is evident in the game’s design as the logo has electricity running through it.

On the reels, you will see A, K, Q, J and 10 royals. The higher value symbols include magnets, switches, Voltmeters, Tesla Coils and scientists. The scientist is the best paying symbol with 2, 3, 4 or 5 on a payline awarding 1, 10, 100 or 500 x your total bet.

Then you have the Book of Fusion wild symbol which substitutes for all symbols. Like the scientist, it pays 1, 10, 100 or 500 x bet (for 2, 3, 4 or 5 in combination). It also acts as a scatter symbol and triggers the main bonus feature (more details below).

Symbol Payouts/Info
book-of-fusion-slot-10-symbol10 3, 4 or 5 = 0.5, 2.5 or 10 x bet
book-of-fusion-slot-j-symbolJ 3, 4 or 5 = 0.5, 2.5 or 10 x bet
book-of-fusion-slot-q-symbolQ 3, 4 or 5 = 0.5, 2.5 or 10 x bet
book-of-fusion-slot-k-symbolK 3, 4 or 5 = 0.5, 4 or 15 x bet
book-of-fusion-slot-a-symbolA 3, 4 or 5 = 0.5, 4 or 15 x bet
book-of-fusion-slot-magnet-symbolMagnet 2, 3, 4 or 5 =0.5, 3, 10 or 75 x bet
book-of-fusion-slot-switch-symbolSwitch 2, 3, 4 or 5 =0.5, 3, 10 or 75 x bet
book-of-fusion-slot-voltmeter-symbolVoltmeter 2, 3, 4 or 5 =0.5, 4, 40 or 200 x bet
book-of-fusion-slot-tesla-coil-symbolTesla Coil 2, 3, 4 or 5 =0.5, 4, 40 or 200 x bet
book-of-fusion-slot-scientist-symbolScientist 2, 3, 4 or 5 =1, 10, 100 or 500 x bet
book-of-fusion-slot-book-of-fusion-wild-scatter-symbolBook of Fusion Wild/Scatter Substitutes for all symbols, pays up to 500 x bet + triggers free spins

Book of Fusion Mobile


Light & Wonder/WMS released Book of Fusion in July 2022 so have created the game using HTML5 technology. This allows for play on mobile, tablet and desktop devices. If you like playing on your smartphone, the game has been optimised for iOS, Android and Windows operating systems.

Book of Fusion Bonus Features

The Book of Fusion slot comes with 1 main bonus feature. It’s all about the free spins where you begin with 2 special symbols which expand to take over the reel. Paying scatter style, every retrigger gives you more free spins plus 2 more special expanding symbols.

Free Spins Bonus feature


The Free Spins Bonus feature is triggered when 3 or more Book of Fusion wild/scatter symbols appear anywhere on the reels. Taking approximately 185 spins to activate on average, 10 free spins are then awarded.

Before the free spins begins, 2 special symbols are chosen randomly. These symbols will expand when they appear on the reels and do not need to land adjacent to each other (i.e. scatter style payouts). Retriggering the feature will also award 2 further special symbols as well as 10 additional free spins.

You can retrigger the feature 4 times which means up to 50 free spins in total. It will also mean all 10 symbols will be special symbols and expand.

Finally, there is a Buy Pass feature. You can enter the Free Spins Bonus feature automatically by pressing the BUY PASS button which will cost 70 x your total bet. This feature isn’t available to UK players though.

Book of Fusion Review Summary – another ‘Book of’ slot but with more special expanding symbols

Theme & Symbols

Sounds & Music

Bonus Features

RTP (95.97%)

Max Win (6,519 x)


Light & Wonder have no ‘Book of’ games in their portfolio so the Book of Fusion slot is the missing ingredient. The mechanic is highly popular with games such as Book of Dead (Play ‘n GO) and Book of Ra Deluxe (Novomatic) becoming some of the most played online slot games ever.

Where Book of Fusion differs is that 2 special expanding symbols are in play right away as opposed to the usual 1. With each retrigger, 2 more expanding symbols are selected. Retriggers can lead to 50 free spins in total plus all symbols expanding. Play ‘n GO’s Legacy of Dead gives you extra special expanding symbols (up to 9) but only 1 per retrigger.

Offering max wins of 6,519 x bet, filling the reels with the highest value symbol, the scientist, will result in a 5,000 x bet payout. The other 1,519 x bet must be from the triggering spin. With an RTP rate of 95.97%, other similar slots offer a higher return rate so it’s a question whether the theme is appealing or not.

If you want a ‘Book of’ game with a difference, Nolimit City’s Book of Shadows slot lets you choose between 10, 15 and 20 paylines. The free spins comes with a special expanding symbol but max wins go up to 30,338 x bet per spin (with 20 paylines).

If you like the science theme, Remember Gulag (Nolimit City) features a white-haired scientist. Another option is Alive! Megaways (Skywind) which is set in Dr. Frankenstein’s lab.

  • 6,519 x bet max wins
  • Free spins with 2 special expanding symbols
  • Nothing original in terms of gameplay

Book of Fusion FAQs

What is the Book of Fusion RTP?

The Book of Fusion RTP rate is 95.97%. This is slightly below the 96% online slots average. The volatility is in the medium to high bracket and will give you a win every 3.02 spins (33.11% hit frequency rate).

What is the Book of Fusion max win?

When it comes to max liability, the most you can win per spin is 6,519 x your total bet. Filling the reels with the high value scientist will result in a 5,000 x bet payout.

Are there any Book of Fusion free spins?

Yes, the Free Spins Bonus feature begins with 10 free spins and 2 special expanding symbols. Each retrigger adds 10 more free spins and 2 more special expanding symbols. This can lead to a total of 50 free spins + 10 special expanding symbols.

Is there a Book of Fusion demo?

Yes, the Book of Fusion demo is available here at Join Nikola Tesla in his laboratory on mobile, laptop, PC and/or tablet devices.