Hold and Win, Sticky Coins and Volcano Multipliers
Once the feature fires, you receive three respins. Every new coin or special symbol that sticks resets the counter back to three, effectively extending the round. In practice a well-fed round can run far longer than the advertised three respins. During testing we recorded rounds stretching into double-digit respins, although we cannot cite a verified average length, because no published dataset exists for this title.
The respin-and-lock mechanic itself is not a 3 Oaks invention. It emerged in the mid-2010s and was popularised by studios including Booongo (now 3 Oaks Gaming), Pragmatic Play and Playson.
Attribution to a single originating studio is contested in trade coverage, so we avoid crediting one developer without a primary source.
Inside the features bonus round, four things can happen on any respin:
- A standard coin lands and locks with its face value, typically 1× to 4×.
- A jackpot coin lands, Mini, Minor, Major or Grand, locking a fixed award instead of a small multiplier.
- A Volcano Multiplier erupts, dropping a badge of 2× to 9× onto active coins. When several multipliers land on the same position, values combine, and that is where the biggest single-round swings come from.
- The Coin Collect symbol appears, the "scorching ball", which instantly gathers every visible coin and jackpot value on screen and adds it to the running total. It is the fastest route to a large round, because it converts an already-loaded grid into one settled payout.
Mystery symbols also feature, transforming into coins, jackpot coins or wild-equivalent symbols. Trade estimates that mystery mechanics contribute roughly 7% to 10% of overall RTP, and that Volcano Multipliers contribute roughly 12% to 15%, are commonly repeated but are not backed by a published maths sheet from the provider. We present them as unverified industry modelling rather than established figures.
Ultra Bonus, the upgraded round. This is the feature most competing reviews miss entirely. Alongside the standard Hold and Win round, Coin Volcano includes an Ultra Bonus, an enhanced version of the respin feature. In Ultra Bonus the volcano erupts more often, high-value coins and multiplier badges appear at a higher rate, and Coin Collect becomes far more relevant to the outcome. Functionally it is the same architecture with a richer symbol distribution, and it is where the theoretical ceiling of 2,550× becomes realistically reachable.