The birds in Pirots do not always play by the same rules. In Pirots 4 they collect symbols; in Pirots X, wins start with matching clusters. That difference is worth knowing before choosing between ELK Studios slots. Below you can browse the games and demos, compare their features and find UK casinos offering ELK titles.
Where to play ELK Studios slots at UK casinos
The reviews below compare online casino operators carrying ELK games. For UK players looking for a particular release, the casino’s own lobby is the place to check before making a first deposit. Slot sites have different selections; a listing for one Pirots game does not mean every sequel is available.
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Try ELK Studios slots in demo mode
An unfamiliar feature is easier to follow when you can see it happen. New players can try ELK slots for free in the demos, which run on virtual credits and award no cash prizes. 18+.
You have viewed 8 of 155 games!
An expanding grid also has to fit on a phone. Open the rules on your device and see whether the smaller symbols and feature meters remain readable. Switching between portrait and landscape may help you find a more comfortable view. Demo results do not predict what a later real-money session will return.
ELK Studios slot games compared: Pirots, Nitropolis and Wild Toro
The gameplay ranges from birds collecting symbols to miniature reels spinning inside larger ones. These four ELK titles illustrate different ways to win and how their bonus rounds change the base game.
| Game | Starting layout | Feature to follow |
|---|---|---|
| Pirots 4 | 6×6 grid | CollectR and grid expansion |
| Pirots X | 5×5 grid | Clusters, wilds and a global multiplier |
| Nitropolis 3 | Six reels and four rows | Nitro Reels inside the main layout |
| Wild Toro | Five reels and four rows | Walking wilds and respins |
Pirots 4 and its expanding CollectR board
Pirots 4 starts on a 6×6 board, with birds collecting symbols through ELK’s CollectR mechanic. A bomb can open up more room on that board. That expansion changes the space available for collecting symbols. Alongside the main board, Lost in Space adds a separate coin feature.
The birds must collect three bonus symbols to trigger free drops. If one is a super bonus symbol, they trigger the super bonus instead. Grid size, collection-meter progress and gem upgrades carry through the bonus, so the board’s development matters beyond the first drop.

Pirots X: a different use for the birds
The familiar characters do not make Pirots X the same game. Wins come from clusters of at least five adjacent matching symbols. A winning cluster leaves a wild symbol behind.
There are two multiplier layers to watch. Connected multiplier wilds multiply the cluster win first, then the global multiplier applies. Birds collecting their respective colours increase that global multiplier. During the free-drops bonus it persists between drops.
Nitropolis 3: reels within reels
The distinctive feature in Nitropolis 3 is the Nitro Reel. A small one occupies two symbol positions but can contain up to 12 small paying symbols. A large Nitro Reel covers six positions and can contain up to six larger symbols.
Three or more bonus symbols trigger free spins, where Nitro Reels remain sticky. The Both Ways feature also allows wins from right to left. These rules belong to Nitropolis 3; a later game in the series needs its own explanation.
Wild Toro: movement across the reels
In the original Wild Toro, the bull moves from reel to reel, generating respins. Its encounters with the matadors can leave a trail of wilds. Three matadors trigger the Matador Respin Challenge.
That moving character makes a useful contrast with the changing grids in Pirots. Look for the original title if this is the version you want: Wild Toro II and Wild Toro 3 are separate releases.
ELK’s catalogue includes the Pirots, Nitropolis, Cygnus and Toro families. Sequels revisit their characters and settings while changing the bonus features and maths models.
X-iter is a separate feature menu offered in some versions of ELK games. Its paid modes vary by title and can include direct entry into a bonus. It is not another name for free spins earned through normal play.
ELK’s global product pages may show modes that are absent from a UK casino version. The Gambling Commission has instructed operators to remove feature buy-in facilities. Do not assume a bonus-purchase option shown in a demo or video will be offered when you open the game at a UK casino.
Our casino game providers guide covers other slot providers and their game ranges.
About ELK Studios
ELK Studios was founded in 2013 in Stockholm, Sweden. Its mobile-first approach has shaped game development from the outset. ELK Studios works with casino operators to distribute its video slots.
Scientific Games announced its acquisition of ELK Studios on 1 December 2021. The acquisition announcement said ELK would continue developing titles independently within the group. Scientific Games subsequently changed its name to Light & Wonder in April 2022.
UKGC and Malta supplier licences
The name to look for in the UK Gambling Commission register is Elkab Studios AB. Account 40844 contains its active remote licence, 040844-R-320591-017, for gambling software and game host (casino) activities.
The Malta Gaming Authority lists Elk Studios Malta Limited under MGA/B2B/605/2018, a licensed B2B critical supply licence covering Type 1 casino gaming services. A casino offering these games still needs the appropriate operator licence for its market.
ELK slots RTP: check the casino’s version
ELK slots do not all have the same RTP. For example, Betfair’s ELK catalogue lists Pirots at 94% RTP. That is a figure for the listed game, not a return promised across ELK’s catalogue.
Look in the game’s information panel for the RTP attached to your version. If it differs from a review or a demo, use the casino version’s figure when comparing. A sequel can also have different rules and maths from the original.
RTP describes a theoretical return over a very large number of plays. It does not mean that staking £100 on a 94% game will leave you with £94. Volatility describes variation in results; neither figure tells you when a win will arrive. Decide what you can afford to spend before playing and stop at that limit.
What does the max win tell you?
A max win is a payout ceiling expressed, for example, as a multiple of the stake. It does not tell you how often that result occurs. When reading ELK Studios slot reviews, check whether the quoted limit applies to the whole game or a particular feature, and confirm it in the game’s rules. A high ceiling alone gives little basis for comparing two slots.
Choosing a game and checking casino bonus terms
Searching for Wild Toro may bring up several ELK Studios games. Wild Toro II and Wild Toro 3 are separate releases, so the sequel number matters when you are looking for a feature you have seen in a review. On a phone, search from the mobile lobby to see whether that release is offered there.
A deposit bonus for new customers may exclude particular games or count their stakes differently towards its wagering requirements. Before using bonus funds on an ELK title, check that game’s eligibility and the offer’s maximum permitted stake. A larger bonus amount is of little use if the game you wanted is excluded.
Latest ELK Studios news
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ELK Studios questions
Does every Pirots game use CollectR?
No. Pirots X uses cluster wins with a global multiplier, while Pirots 4 uses CollectR. The series name alone does not identify the win system.
Why is an X-iter option missing at my UK casino?
Game versions differ by market. ELK’s global pages describe paid modes including bonus purchases, and the Gambling Commission has required operators to remove feature buy-ins. A global demo is therefore not a complete guide to the options in a UK casino version.
What carries over during Pirots 4 free drops?
Grid size, collection-meter progress and gem upgrades persist during the bonus. The expanded board and upgraded gems therefore remain part of the feature as the drops continue.

Daniel is a content creator at Mr Win and has worked in the iGaming industry since 2012. With more than a decade of experience reviewing casino operators and bonuses, he focuses on safe play, licensing standards, and helping players find fair gaming sites.
Fact checked by: Greg – Casino expert. Last fact-checked: September 28, 2026.
