Book of Ultimate Infinity

Book of Ultimate Infinity is SG Digital's crack at combining two distinct slot mechanics into one release: the classic expanding-symbol book bonus and ReelPlay's licensed Infinity Reels system. SG Digital is one of several studios to license the Infinity Reels mechanic, and here it's wrapped in a familiar Ancient Egyptian setting — pyramids on the horizon, the Nile winding through palm trees and temples, with an Arabian-inspired soundtrack tying it all together.

The Infinity Reels mechanic is the real draw. Every spin begins with three reels showing four symbols each; land at least three identical symbols across those opening reels and a fourth reel is added for another shot at extending the win, with the process repeating as long as the newly added reel keeps contributing. The reel count is capped at 50 rather than being truly infinite, but the growth mechanic still creates a satisfying sense of escalation with each additional reel. The first added reel brings a x2 win multiplier, which then climbs by +1 for every subsequent reel — a structure that rewards sustained combinations rather than one-off hits. Winning combinations themselves form from five or more matching symbols counted from the first reel onwards, with payout scaling by the total number of symbols in the chain multiplied by their individual value.

Layered on top of that modern engine sits the traditional book-slot bonus: a chosen symbol from a dusty old tome expands across full reels once free spins are triggered, giving Book of Ultimate Infinity a genuine blend of old-school and contemporary mechanics rather than just borrowing the Infinity Reels license as a gimmick.

On the numbers, the game posts a comfortably above-average 96.5% RTP alongside high volatility, and rather than a multiplier-based max win, it carries a fixed $250,000 cap on total winnings — a structure more commonly seen in games designed for large-scale, high-stake play. Stakes run from 0.20 up to 50 per spin. Getting to the free spins round does require some patience, as the volatility can produce stretches without much action before the reels start expanding meaningfully.

Symbol-wise, expect J-A card royals at the lower end, stepping up through knives, Ankhs, a queen and a gold statue toward the premium Pharaoh symbol at the top of the paytable.

For players who want the familiar book-slot free spins concept married to a genuinely different core mechanic, Book of Ultimate Infinity offers real novelty within a well-worn genre. The combination of high RTP and a capped dollar-value ceiling makes it a distinctive option worth exploring.

Ready to see how far the reels can expand? Try Book of Ultimate Infinity for free in demo mode at johnessyslots before chasing that $250,000 cap for real.