Book of 99 Slot Review by Relax Gaming: RTP, Features, and Gameplay Insights
Relax Gaming’s Book of 99 is a standout in the world of online slots, not least because of its exceptional RTP of 99%, a figure rarely seen in the industry. This high return-to-player rate immediately positions it as an attractive option for both casual players and serious gamblers who are seeking better long-term value from their spins.
In this review, we’ll explore what makes Book of 99 more than just another “Book”-style slot. From its symbols and mechanics to design and strategy tips, this guide covers everything you need to know before trying it out at online Grosvenor casino or any other platform featuring Grosvenor casino slots.
General Information About the Slot Book of 99
Book of 99 was developed by Relax Gaming and released in May 2021. It’s a 5-reel, 3-row video slot with 10 paylines and a mythological Greek theme. The story revolves around Odysseus and his epic journey, adding narrative depth to the standard slot experience.
The standout feature is, of course, the sky-high RTP of 99%, which is practically unheard of in the current online slot landscape. For players who are mathematically inclined, this return makes the game one of the best choices in terms of value per spin.
This title is fully optimised for both desktop and mobile play, ensuring a smooth gaming experience regardless of device. The layout and controls are intuitive, making it accessible even to players who are new to Grosvenor casino slots or similar games.
Features and Technical Parameters
Book of 99 features a classic setup with 5 reels, 3 rows, and 10 fixed paylines. The slot is highly volatile, meaning players can expect less frequent but potentially larger wins. This makes it suitable for those who enjoy a high-risk, high-reward style of gameplay.
The 99% RTP is not just a marketing gimmick—it’s backed by a smart mechanic. Every non-winning spin contributes to a meter. Once it reaches 99, players are rewarded with a free spins bonus round, making every spin feel meaningful even when not winning.
The slot’s minimum bet starts at just £0.10, with a maximum of £100 per spin. This wide range accommodates a broad spectrum of players, whether you’re experimenting casually or playing with a more serious bankroll strategy at online Grosvenor casino.
Symbols and Payouts
The highest paying symbol is Odysseus himself, offering up to 5,000x your stake for a full line. Other premium symbols include mythical figures and artefacts, each rendered with intricate detail that adds visual appeal while offering lucrative payouts.
Lower-paying symbols are represented by classic playing card values (10 to A), which, while more common on the reels, still contribute to frequent small wins and help keep the balance steady during gameplay.
The Book symbol serves both as the wild and scatter. It substitutes for any other symbol to complete winning lines and also triggers the free spins feature when three or more land anywhere on the reels. This dual function boosts both base game and bonus potential.
Gameplay Features
The free spins round is the heart of Book of 99’s gameplay. Triggered by landing three or more Book symbols or via the collection meter, this feature awards 10 free spins. Before spins start, one symbol is randomly chosen to expand during the bonus.
Expanded symbols cover entire reels and pay from any position, not just left to right. This mechanic significantly boosts the potential for massive wins, especially when high-value symbols are chosen.
Unlike some slots that limit bonus frequency, Book of 99’s collection meter ensures that players are guaranteed regular access to the free spins feature, making it a more engaging option on platforms like Grosvenor casino slots.
Design and Sound
Visually, Book of 99 is polished and atmospheric. The game immerses players in ancient Greek mythology, complete with scroll-covered reels, temples in the background, and characters drawn with precision and artistic flair.
The animations are smooth, enhancing both base game and bonus features. Symbols glide onto the reels with fluidity, and winning combinations are highlighted with satisfying visual effects that never overwhelm the senses.
The soundtrack is equally well-designed. A subtle orchestral score accompanies the gameplay, building tension during key moments like near-wins or the start of free spins. The overall presentation supports an immersive yet focused gaming experience.
Advantages and Disadvantages of Book of 99
Among the key strengths are its industry-leading RTP, engaging free spins mechanics, and beautiful design. The inclusion of a guaranteed free spins trigger through the 99-spin meter also adds a strategic layer to play that many other slots lack.
However, the high volatility may not suit everyone. Players who prefer frequent, smaller wins might find the dry spells frustrating. Also, those expecting multi-level bonuses or mini-games may find the game a bit too traditional in structure.
Tips on Strategy and Bankroll Management
Given its high volatility, it’s crucial to set a budget and stick to it. Patience is key—remember that the collection meter builds value over time, so maintaining a consistent stake helps in maximising the bonus round when it arrives.
A practical tip is to play at modest bet levels until you’re familiar with the game’s rhythm. Then, if comfortable, consider increasing your stake during bonus rounds. With smart bankroll management, Book of 99 can become a rewarding addition to your online Grosvenor casino rotation.