As great as regular slots are, we have to admit that sometimes we want to play something different. This is where different slot mechanics and formats come in, and these have only grown in popularity over the past few years. One of these is the subject of this very blog post, the cluster slot. Sometimes known as grid slots, cluster slots shift the game away from traditional paylines to something that’s closer to a puzzle game. We’re great fans of cluster slots, and have been looking for best examples of the form released in 2025. Which ones are our favourites? Continue reading to find out, of course!
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What are Cluster Slots?
A number of elements make a cluster slot, but the most obvious one is in the name - it’s’ a game about clusters, as opposed to paylines. This means winning combinations are formed by landing a number of matching symbols, typically 5 or more, in horizontally or vertically adjacent positions. The game itself still consists of reels and rows, but here they are typically referred to as a grid. The game grid is typically square and larger than that of traditional slots, with sizes of 6x6 and 7x7 not uncommon among cluster slots.
Developers of cluster slots keep the action exciting by adding other mechanics to the gameplay. The chief of these is cascades, which remove the winning symbols from the grid and then drop new ones to fill the empty spaces. This can lead to new winning clusters, in which case this process repeats until there are no more wins in view. Cascades can be linked to a progressive feature that grows with each consecutive cascade or a symbol collecting feature that triggers a game modifier whenever you collect the required amount of a type of symbol. The result is exciting, volatile gameplay with solid win potential and plenty of visual flourish.
2025’s Best Cluster Slots!
Now that we explained what a cluster slot is we should get straight to our favourite games of this type of 2025. We’ve based these top cluster slots on a number of factors, including RTP, win potential, volatility, game features, and even personal preferences. The list itself is in no particular order, so it’s up to you to find out which of these titles is truly your best cluster slot of 2025.
Tsar Wars (Nolimit City)
Tsar Wars (Nolimit City)
Nolimit City is well known for quirky, if not outright edgy, slots, and Tsar Wars is no exception to this rule. After all, Tsar Wars is a cluster slot that combines Russian history with, yes, Star Wars. The result is a highly volatile take on Moon Princess, with three characters each with a unique random modifier. Will you get the Wild Rush, Force Shift, or xBomb Wild? Those are not the only bonus features on offer, as symbols can land in sizes of up to 3x3 while the cascade mechanic is tied to a progressive multiplier that grows by +1 with each cascade.
Rainbow Princess (Hacksaw Gaming
Rainbow Princess (Hacksaw Gaming)
Another cluster that is reminiscent of Pragmatic Play’s Moon Princess, Rainbow Princess is the Hacksaw Gaming take on the genre. This is a medium volatility game set on a 6x5 grid where wins are formed with clusters of 5 or more matching symbols. Get a winning cluster and it will leave a Magic Frame in a random position on the grid. If this position gets a winning cluster on the same spin this will apply a random multiplier of up to 100x to the payout! Frames remain in the same position during cascades and double in size if they hold winning symbols.
Oxygen 2 (ELK Studios)
Oxygen 2 (ELK Studios)
Head back to the water in Oxygen 2, the sequel to the 2023 ocean-themed cluster slot from ELK Studios. The game takes place on a 6x7 grid packed with all manner of underwater critters acting as the paying symbols. Winning symbols explode and leave an oxygen bubble in their space. Get another win in a space with an oxygen bubble during the same spin and its multiplier will grow by +1. Multipliers start at 1x and can reach all the way up to 2,048x with enough consecutive wins.
Book of Monsters
Book of Monsters
No, Book of Monsters is not a “Book of”-style slot - it is, instead, a Play’n GO cluster pays game with a cute monster theme. The titular Book of Monsters can be found on the right-hand side of the screen, and will flip open to reveal free spins and a randomly selected fat symbol. This is a symbol up to 7x7 in size. Like many other cluster slots wins are formed by landing at least 5 matching symbols in vertically or horizontally adjacent positions, while landing 4 or more scatters triggers the free spins round.
Spinfection
Spinfection
AvatarUX brings a bold visual style and wins of up to 10,000x the stake in Spinfection. This game is all about the cascades, as wins leave a multiplier on the symbol’s position after it pops off the grid. This multiplier can continue growing if more winning symbols land on the same space. Look out for the wilds, as these don’t pop off whenever they make part of a win. Instead a wild will move to a random position on the 7x7 grid for more chances to win. Get 3 wilds on the grid for a round of free spins where multipliers don’t reset back to 1x between spins.
Why are Cluster Slots so Popular?
The cluster slot format was an instant hit ever since the first game in the genre, Aloha! Cluster Pays, hit the scene, and have only grown in popularity these days. In part this is due to players getting a bit bored of traditional paylines–based slots, in which case cluster slots fit the bill perfectly. They are still very much slots, but the cluster mechanic brings something new and exciting to the table. Then there’s the fact that a lot of cluster slots are exciting, high volatility affairs with big win potential to match. Want a chance to win a good sum? Then cluster slots are where it’s at. These are truly modern slots, and ones that are guaranteed to bring plenty of fun for your gameplay buck.
Enjoy a Cluster of True Slot Gaming!
With their mix of novel gameplay and win potential there’s no wonder that cluster slots have caused such a splash in the online casino scene. Every year brings more of these games, making our task of finding our favourites just that little bit more difficult! So do enjoy these games and let us know which ones you like best. Of course, do play our recommended cluster slots, as well as all other games, responsibly. Set a bankroll for playing slots, and stick to it. Make small bets and remember that these are games of pure chance, so never chase your losses. With all of this in mind you’ll be all set to enjoy cluster slots safely and with peace of mind.
