Book of 99 Slot Review

Book of 99 Slot RTP, Details & Wager Limits

The Book of 99 slot is played on a classic 5 reel, 3 row machine with 10 active paylines. To create a winning combination, land 3, 4 or 5 matching symbols or wilds from left to right on 1 of those paylines, starting from reel 1. With the 4 higher value symbols, only 2 (or more) are required in combination. Things are slightly different with the expanding symbols in the bonus feature which we’ll look at below.

Stake levels in range from 10p to £100 per spin thus catering to all players and pockets. Use the + and – tabs below the reels to set your desired stake. Non UK players can opt for Turbo Mode and Autoplay. The latter allows infinite autospins with optional loss, win and single-win limits.

As impressive as the design and gameplay are, what really makes Book of 99 stand out is the return to player rate. The Book of 99 RTP is 99%. That’s the best number I’ve seen from any online slot and much higher than you’ll find from most slots which usually hover around the 96% mark.

If the RTP rate is important to you, check out the slots with the highest RTP. The good news is that there is no other RTP version.

When it comes to variance, it’s high as you’d expect. It’s ranked as 5/5 by provider Relax Gaming. There’s a 29.83% hit frequency rate so nearly a third of spins will give you a winning combination (a win every 3.35 spins on average).

The Book of 99 max win is 5,000 x your total bet per spin. However, the max simulated win is 12,075 x your total bet which was surely achieved in the Free Spins feature as a whole. The best opportunities of winning big come in the free spins due to the expanding symbol. A screen full of Apollo symbols will result in the max payout.

Theme: head to ancient Greece and battle amongst the gods

The Book of 99 slot has an ancient Greek theme. With terrific design, it features mythological characters such as the giant one-eyed Cyclopes.  You are taken to a battle amongst the gods. The comic book visuals are complemented by a rather haunting backing track that adds to the air of mystery.

Set against a rustic, night-time backdrop, the reels here are set within marble columns. There you’ll find A to 10 symbols in precious metals and embedded with gemstones.  They’re joined by a quartet of higher value symbols. There’s Lamia (a female daemon), cyclopes (the one-eyed monster) Pythia and Apollo. Apollo is the most rewarding symbol. Land 2, 3, 4 or 5 of these on a payline and you’ll win a payout equal to 1, 10, 100 or 500 x your total bet.

The Book symbol serves a dual role. It’s a wild that substitutes for all the standard symbols (apart from the expanding symbol in the bonus round). Landing 3 of them on the same spin triggers the Free Spins feature. Here’s a table highlighting payouts and functions for all Book of 99 symbols:

Symbol	Payouts/Info
10	3, 4 or 5 = 0.5, 2.5 or 10 x bet
J	3, 4 or 5 = 0.5, 2.5 or 10 x bet
Q	3, 4 or 5 = 0.5, 2.5 or 10 x bet
K	3, 4 or 5 = 0.5, 4 or 15 x bet
A	3, 4 or 5 = 0.5, 4 or 15 x bet
Lamia	2, 3, 4 or 5 = 0.5, 3, 10 or 75 x bet
Cyclopes	2, 3, 4 or 5 = 0.5, 3, 10 or 75 x bet
Pythia	2, 3, 4 or 5 = 0.5, 4, 40 or 200 x bet
Apollo	2, 3, 4 or 5 = 1, 10, 100 or 500 x bet
Book Wild/Scatter	Substitutes + triggers Free Spins feature

Book of 99 Mobile

Released on the 4th of May 2021, Book of 99 is available to play on all devices including smartphones, tablets and computers. You’ll find the same classy design and simple gameplay in all versions. Most importantly, the 99% RTP is present and correct no matter what device you’re using.

Book of 99 Bonus Features

In the Book of 99 slot game, the gameplay is straightforward. Free spins with special expanding symbols are the main feature offering. Slightly unusually, there are 2 ways to trigger the free spins.

Free Spins feature

Land 3 or more wild symbols on the same spin to activate the Free Spins feature. Your reward here is 10 free spins. Before the free spins begin, 1 of the standard symbols is picked at random. This will be the special expanding symbol for the whole of the feature.

On each free spin, a standard payout consideration is made. If a special symbol lands, it expands to fill the whole of the reel. In addition to standard payline wins, the special expanding symbol can pay out on all 10 paylines depending on how the symbols fall.

Winning combinations made up of the expanding symbol don’t have to be connected either. For example, expanding symbols on reels 1, 3 and 5 would result in a winning combination being formed in the free spins. Now, your max win depends on which symbol becomes the special expanding symbol:

Now, landing 3 or more wild symbols will result in a retrigger and another 10 free spins. Like slots with a similar bonus feature, there’s no limit to how many free spins you can play with.

Collection feature

There’s a second way to trigger the Free Spins feature. Each time a wild symbol lands, it’s collected in a meter to the left of the reels. This is called the Collection feature.

With each wild, you’ll progress along a treasure map. When you have amassed 99 wilds, you’ll trigger the free spins. These come with the expanding symbol just like in a standard trigger. When you’ve played out your 10 free spins, the meter resets and you’ll start collecting wilds once again on a quest to reach 99.

Book of 99 Review Summary: it’s all about the 99% RTP

I’ve played plenty of slots that come with free spins and an expanding symbol. Such as Book of Dead (Play ‘n GO) and Book of Ra Deluxe (Novomatic). Whilst the design may not be top-notch, the Book of 99 slot has all the elements you’d expect from a ‘Book of’ game. It has the added Collection feature which gives you an extra way to get into the free spins.

However, what sets the Book of 99 slot apart is the 99% RTP rate. You won’t find a better figure than that anywhere. With its impressive sound and visuals and classic bonus feature, Book of 99 would be a perfectly playable slot if it had an average RTP rate.

With that number standing at 99%, it becomes well worth considering if you enjoy the ancient theme. The key to big wins is to get a high value special expanding symbol in the free spins. This could be the difference of 100 or 5,000 x bet payouts per free spin. That said, the average win in the free spins is 68.8 x your total bet so bear that in mind. The max simulated win of 12,075 x bet is impressive.

Whether this will nudge other slot developers into inching up their RTP rates remains to be seen. However, some slot sites may not include Book of 99 in the wagering for their welcome bonuses or free spins due to the high RTP rate. That remains to be seen.