Searching for an honest Book of Grimm review before you commit real money? You're in the right place. Holle Games are the developer behind it, tuning the slot for a medium low-variance maths model, with an RTP of 95.43%. Visually it's wrapped in a fantasy theme, with the action running on 30 paylines across 5 reels. Top wins are capped at 5,000x your stake, a healthy ceiling worth chasing. So does it deliver? Let's get into it.
Written by Alex Crawford · Last updated: February 2026
This title, Book of Grimm, is the work of Holle Games, built around a fantasy theme. It runs on a 5-reel grid running 30 paylines with medium low variance, and an RTP of 95.43%.
Dig into the bonuses and Book of Grimm starts to stand out. Look out for scatter symbols that unlock free spins and extra bonus rounds. The medium low volatility makes it forgiving on the bankroll, ideal for relaxed, longer sessions. Overall it's a well-rounded title that knows what it is.
At 95.43%, the RTP is slightly below the industry average of ~96%. While this is typical for many popular slots, players should be aware of the slightly lower theoretical return.
Medium-low volatility offers a good balance of regular wins with occasional larger payouts. Expect frequent hits with modest amounts, suitable for casual players who want low-risk entertainment.
About 1 in 3 spins results in a win. This is a moderate hit frequency that balances win frequency with payout size.
Book of Grimm features scatter symbols that can trigger free spins rounds. Landing the required number of scatter symbols anywhere on the reels activates the free spins feature, giving you extra chances to win without additional bets. During free spins, special modifiers may apply to boost your winning potential.
3.0 / 5 — Good
Book of Grimm by Holle Games is a solid offering that delivers good entertainment value. The 95.43% RTP combined with medium low volatility creates a well-balanced gaming experience.