Reactions & Cascading Wins Explained
How the reactions (cascading reels) feature in Megaways slots works, how win streaks build, and which titles do it best.
Reactions — also called cascades, avalanches or tumbles — are central to how Megaways slots play and pay. Here is how they work.
Winning symbols disappear
When you land a winning combination, those symbols are removed from the reels and the symbols above drop down to fill the gaps, with new ones falling in from the top. If the new arrangement creates another win, it pays too — and the process repeats. A single spin can chain several wins this way.
Where the multipliers come in
In the base game, reactions simply give you extra chances to win from one spin. In the free-spins bonus, most Megaways slots attach a win multiplier that increases with every successive reaction and — crucially — does not reset between spins in the bonus. That escalating multiplier is how Megaways slots produce their headline wins.
Keep learning
This guide is part of our wider library. To go deeper, read what are Megaways slots, how Megaways works and volatility explained. Every term is defined in our Megaways glossary, and you can put it all to work on our best Megaways casinos ranking.
Frequently Asked Questions
Is this guide specific to UK players?
Yes. Everything here reflects UK Gambling Commission rules as they stand in 2026, including the 2025–2026 changes to stake limits and player protection. We only cover UKGC-licensed casinos.
What are Megaways slots?
Slots using Big Time Gaming's variable-reel mechanic, giving up to 117,649 ways to win that change every spin. See our full explainer.
How many ways to win do they have?
Up to 117,649 on a maximum spin, when all six reels show seven symbols. The number changes each spin. See ways to win explained.
What RTP do Megaways slots have?
Typically 94% to 96.5%, but many ship in several RTP versions and the casino picks which to run. Always check the game info. See Megaways RTP explained.
Why are Megaways slots so volatile?
The huge number of ways to win and escalating bonus multipliers concentrate the return into rare big wins. See volatility explained.
Are Megaways slots fair?
Yes — at UK-licensed casinos they run on independently tested RNGs that cannot be altered. They carry a house edge, so they are fair but favour the casino over time. See are Megaways slots rigged.
Who invented Megaways?
Big Time Gaming, which launched it on Bonanza in 2016 and licenses it to other studios. See our history of Megaways.
What is the best Megaways slot?
Bonanza is the original; Fishin' Frenzy, Big Bass, Gonzo's Quest and Rainbow Riches Megaways are also hugely popular. It depends on the features and volatility you want. See best Megaways slots.
Can I play Megaways slots for free?
Yes — most casinos offer demo mode, a good way to learn a title before staking real money. See Megaways free play.
Did UK rules on slots change recently?
Yes — stake limits of £5/£2 a spin, independent testing and fund protection all apply to Megaways slots. See our 2026 rules guide.
How do you stay independent?
We earn affiliate commission on sign-ups, but it never affects our rankings, which follow the published method in our methodology. We only list licensed casinos and publish every correction.
How do I play Megaways responsibly?
Treat them as high-volatility entertainment, play at affordable stakes, set a deposit limit and never chase losses. Free help is on 0808 8020 133. See responsible gambling.