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Book of 99 Slot

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Our rating:
  • A MASSIVE RTP of 99% really sets this game apart
  • RTP blows most other slots out of the water
  • It’s a shame they didn’t do more with the features

Book of 99 slot from Relax Gaming is, as you might have guessed from the title, another ‘expanding symbol’ slot that is trying to compete with the likes of Book of Dead from PlayNGo, one of the most popular slots of all time. It’s not the first company to try and compete, but they have a very enticing prospect that gives them a real shot – the RTP. 99 is quite an important number in this game as it links to a number of things, one of which is the RTP which is also 99%. This is incredibly high, much much higher than almost every other slot out there and that makes it a very intriguing game, regardless of the features. That said, let’s see just what this game has in store before you decide to go ahead and play it. There are 10 pay lines in the game where you need to land base symbols to get a win which are as follows, ranked in ascending order based on their value:

  • 10, Jack or Queen
  • King or Ace
  • Feline or Troll
  • Witch
  • King

There is a wild symbol as well, shown as a book, which substitutes for all other symbols in a winning combination apart from the expanding symbol in the free spins bonus.

book of 99 slot gameplay


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Book of 99 Slot Bonuses and Features

Free Spins Bonus. For this you’ll need 3 or more wild symbols anywhere on the screen at the same time, giving you 10 free spins. Here, a special expanding symbol is chosen at random which can expand whenever it lands and pay out on all 10 pay lines, even if not connected from left to right.

Collection. Every wild symbol you land in the game will be added to the meter seen on the side of the reels. Once you reach 99 collections, you will automatically trigger the free spins bonus. This will be played at the average bet size when collecting each wild.

book of 99 slot rules


Book of 99 slot from Relax Gaming is a simple game with no features in the base game and a free spins bonus that is all too familiar. They’re not exactly trying to hide the fact that this is a direct competitor to the Book of series. However, there is one very important difference, the RTP. The RTP here is a staggering 99%, far higher than the average 96% and something you almost never see. This really does make it a very appealing alternative and one you might want to consider. It is a shame they didn’t put a bit more time into making the base game more interesting as there’s nothing to it, but with an RTP like that it’s still a very enticing option. You can find other slots from the developer here too.

book of 99 slot signup

A HUGE RTP really sets this slot apart





  • Massive RTP,
  • Still a pretty good free spins bonus.


  • Base game is dull.

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