Cluster slots, also known as ‘grid slots’ and ‘cluster pays slots’, are a popular and innovative type of online casino slot machine games. They were first introduced by NetEnt in their slot, Aloha: Cluster Pays, in May 2016. These slots deviate from the traditional 10 or 15 payline structure, instead paying out when symbols appear in clusters.
Different Types of Slot Games
See the 7 different types of online slot games below to compare features and gameplay mechanics first.
The Latest ‘Cluster Pays’ Slots to Play
Cluster Slot | Provider | RTP |
---|---|---|
5 Monsters | Relax Gaming | 96.4% |
Buster’s Bones | NetEnt | 96.1% |
Chain Reactors Deluxe | Light & Wonder | 96.0% |
Champions of Olympus | Gold Coin Studios | 96.1% |
Celestial Beauty | Skywind | 96.5% |
Jelly Multihops | Red Tiger Gaming | 96.2% |
Jiggly Cash | Thunderkick | 96.5% |
Viking Fury Spinfinity | Blueprint Gaming | 96.0% |
Viking Runecraft Apocalypse | Play’n GO | 96.0% |
Wildman Super Bonanza | Pragmatic Play | 96.6% |
Gameplay and Grid Format
Cluster slots typically feature a grid format, where symbols are arranged in 8 or more rows and 5 or 6 columns. To win, you need to form clusters of matching pay symbols, either horizontally or vertically (see image).

The minimum number of symbols required for a win varies depending on the game, but it generally ranges from 4 to 6.
Volatility and Return to Player (RTP)
Just like most other European slot games, cluster slots have 3 levels of volatility, ranging from low to high. This means that some cluster slots may offer more frequent but smaller payouts (low volatility), while others may provide less frequent but larger payouts (high volatility). The return to player (RTP) also varies among all cluster and grid-type slots, with some games featuring higher RTPs than others. The average RTP across the listed newest cluster pay slots is 96.14%.
This is calculated by summing up all the individual RTP percentages of the slots and then dividing this sum by the total number of slots. The individual RTPs are as follows:
- 5 Monsters: 96.4%
- Buster’s Bones: 96.1%
- Chain Reactors Deluxe: 96.0%
- Champions of Olympus: 96.1%
- Celestial Beauty: 96.5%
- Jelly Multihops: 96.2%
- Jiggly Cash: 96.5%
- Viking Fury Spinfinity: 96.0%
- Viking Runecraft Apocalypse: 96.0%
- Wildman Super Bonanza: 96.6%
As there are 10 slots, we divide this sum by 10: 961.4 / 10 = 96.14%.
- Tip: Consider both volatility and RTP when choosing the best cluster pays slots with high payouts. An RTP of 96% is generally considered optimal.
Cluster Wins and Cascading Reels
One of the main attractions of grid-type cluster slots is the cluster win mechanic, which allows players to win by forming clusters of matching symbols. This is further enhanced by the cascading reels feature, where non-winning symbols are removed from the grid, and new symbols drop into place, potentially creating additional wins on top of excisting ones.
The tumbling feature can lead to multiple consecutive wins.
Special Symbols and Features
All grid cluster pays slot games include various special symbols and extra in-game features to make the gameplay more interesting. Some common elements found in cluster slots are:
- Scatters trigger bonus rounds or free spins when they drop in the required amount, usually three;
- Wild Symbols substitute for any other symbols, except scatters, to form winning clusters;
- Multipliers increase the payout of winning clusters if they drop next to them;
- Sticky Wilds remain in position until no more wins occur or during an entire bonus round;
- Expanding Symbols cover multiple grid positions both vertically and horizontally, enabling more chances to win.
Bonus Rounds and Free Spins
Popular cluster slots also feature bonus rounds and free spins, which can be triggered by specific symbols or conditions. These bonus features often include sticky wilds, extra wilds, boosted multipliers, transforming symbols, chain reactions, additional free spins, or other gameplay enhancements.
Some cluster slots, like Good Luck Clusterbuster Jackpot by Red Tiger, also offer progressive jackpots, where a portion of each bet contributes to a growing jackpot prize.
These jackpot prizes can be won by meeting specific game conditions or triggering a random special bonus round.
Thematic Designs, Sound Effects, and Graphics
All the latest slots of 2023 with the cluster pays setup come with modern designs, engaging sound effects, and high-definition graphics, resulting in audiovisually appealing gameplay (see our video below).
Grid cluster games, where symbols must land adjacent to each other and meet at one of the 4 corners, come with popular themes such as fantasy, adventure, mythology, and retro touch, among others.
Mobile Compatibility and User-friendly Interface
Today, most of the content available on desktop computers is undoubtedly available on mobile devices. Consequently, all the newest cluster and Megacluster slots that you can find in the table above are designed with mobile compatibility in mind.
Cluster Pays Slots Worth a Spin
Retro Tapes by Push Gaming is our favoured cluster pays slot game that rewards by forming clusters of similar symbols.
Feature | Description |
---|---|
Maximum Win (Observed & Theoretical) | 10,000x |
RTP | 96.47%, 94.46% |
Volatility | High |
Bonus Buy | Available |
Wild Multiplier Symbol | Available in Base Game and Top Charts Feature |
Magnet Feature | Picks a Paying Symbol and forms a cluster |
Top Chart Feature | Lands random symbols during Free Spins |
Cluster Links Feature | Forms clusters for instant wins |
Instant Prize Symbols | Values: 1x, 2x, 5x, 10x, 25x, 50x, 100x, 250x, 500x, 1000x |
The game features a retro theme and has special components like the Wild Tape Symbols and the Tapes & Instant Prize feature. The Wild Tape Symbols substitute for other symbols (except Magnet and Wild Multiplier Symbols), and increase their multiplier value each time they contribute to a win.
Three or more Wild Tape Symbols trigger the Free Games Feature. In the Tapes & Instant Prize feature, tape clusters yield instant wins based on the tape symbol value and the cluster type. The Instant Prize Symbols act as bet multipliers, and the Wild Multiplier Symbol not only boosts winnings but transforms into an Instant Prize Symbol after awarding its multiplier.
Both can happen during both the base game and the Top Charts Bonus, improving the game’s winning potential.
Retro Tapes has also three special bonus features: the Magnet Feature, the Top Charts Feature, and the Cluster Links Feature. Below is our video with gameplay for a better understanding of the game concept.
Retro Tapes has two RTP percentages: 96.47% and 94.46%. And the game’s maximum win, both theoretically and observed, is 10,000x. As a high volatility cluster slot game, Retro Tapes has less frequent payouts, with possible large wins when they do occur.
There is also an in-built “bonus buy” option similar to other feature buy slot games available (see image below), providing a quick opportunity to buy a free spin bonus game instead of waiting to trigger it during gameplay naturally.
Casinos to Play Cluster Pays Slot Games
Iconic online slot games with cluster pay mechanics, like Reactoons, Jamin’ Jars, Sweet Bonanza, and Sugar Rush, are popular choices among many gaming enthusiasts.
Among the top casinos offering these games are several EU casinos such as Bitstarz, Winz, CasinoFriday, Mount Gold, SlotVibe, and others.
These casinos offer a broad range of casino games and are recognized for their varying features, like deposit bonuses, game providers, support services, and convenient payment methods.
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FAQs on Cluster Pays Slots Answered
- What exactly are cluster pays slots?
- Cluster pays slots, also known as ‘grid slots’ or ‘cluster-based slots’, feature a unique gameplay mechanic where you form winning combinations via clusters of matching symbols. Unlike traditional slots based on paylines, these games pay out when identical symbols are adjacent to each other in a cluster of five or more, either horizontally or vertically.
- How is the grid format structured in cluster pays slots?
- The grid in cluster pays slots is usually structured with 5-10 rows and 5 or 6 columns.
- What does the volatility in cluster pays slots mean?
- Volatility represents the level of risk in cluster pays slots. Low volatility results in frequent but smaller wins, medium volatility offers a balanced frequency and size of wins, and high volatility leads to less frequent but potentially larger wins.
- What is the average RTP in cluster pays slots?
- The average return-to-player (RTP) in cluster pays slots is 96.14%, based on real data.
- What is the cluster win mechanic and cascading reels feature?
- The cluster win mechanic replaces traditional paylines with clusters of 5 or more identical symbols for a win. The cascading reels feature—also known as tumbling reels or the avalanche feature—causes winning symbols to vanish, making room for new symbols to fall into place. This can create additional wins and the process can repeat, allowing for multiple wins in a single spin.
- What are some cluster pays slots’ special symbols and features?
- Special symbols and features in cluster pays slots include scatter symbols that activate bonus rounds, wild symbols that replace other symbols for wins, multipliers, sticky wilds, expanding symbols, and more unique elements to enhance gameplay.
- How do cluster pays slots bonuses and free spins work?
- Bonuses and free spins in cluster pays slots are usually activated by special symbols or specific conditions. These bonus features can come with enhancements like higher multipliers, additional wilds, transforming symbols, or chain reactions for successive wins. Some even feature progressive jackpots.
- What are some popular themes in grid slots?
- Cluster pays slots come in various themes, from fantastical worlds to mythology and retro styles. These themes often feature eye-catching designs, captivating soundtracks, and high-quality graphics.
- What other types of online slots are there besides cluster pays?
- Besides cluster pays slots, other popular online slots types include video slots, classic slots, jackpot slots, megaways slots, mobile slots, branded slots, 3D slots, i-slots, and VR slots. If you’re interested in diversifying your playing experience, you can explore a variety of casino games available.