How slot features work
Every bonus round, wild and reel trick, taken apart: what triggers it, what it does to the game's maths, and which games in our library use it.
Ways to win
Megaways
A ways-to-win mechanic where the number of symbols on each reel changes every spin, so the count of winning ways changes too.
Ways to win
A pay system that counts every left-to-right path of matching symbols on adjacent reels instead of using fixed paylines.
Paylines
Fixed patterns across the reels that symbols must land on, usually left to right, for a spin to pay.
Cluster pays
A pay system where groups of matching symbols touching each other on the grid win, with no lines or reels-from-the-left rule.
Pay anywhere
A pay system where enough of the same symbol anywhere on the screen wins, with no need to be adjacent or on a line.
xWays
A Nolimit City mechanic where special symbols reveal several copies of one symbol, multiplying the number of ways to win on that spin.
Infinity Reels
A mechanic where each winning spin adds a new reel to the right, so the grid keeps growing until a spin produces no new win.
Reel behaviour
Cascading reels
After a win, the winning symbols are removed and new ones fall into the gaps, giving another chance to win from the same stake.
Respins
An extra free spin of some or all reels, usually with certain symbols held in place, triggered by a symbol or a win.
Grid expansion
A feature that adds rows, reels or positions to the grid during play, increasing the ways or space for wins.
Player choices
Nudges and holds
Fruit-machine features that let a reel move one position (nudge) or stay put while others spin again (hold).
Bonus buy
An option to pay a set multiple of the stake to go straight to a slot's bonus round. Not offered on GB-licensed sites.
Gamble feature
An optional side game after a win that lets you risk it to double or multiply it, usually by guessing a card colour or suit.
Ante bet
An optional extra stake on each spin that raises the chance of triggering a bonus. Not offered on GB-licensed sites.
Wilds & symbols
Split symbols
A symbol that counts as two or more of the same symbol in one position, raising the count for a ways or line win.
Expanding wilds
A wild symbol that grows to cover its whole reel (or more) when it lands, substituting in every position it covers.
Sticky wilds
A wild that stays in place for more than one spin, usually through a respin sequence or a whole free spins round.
Walking wilds
A wild that moves one position or reel along the grid on each respin, awarding a free respin each time until it walks off.
Multipliers
A value such as ×2 or ×10 applied to a win, a spin or a whole feature, multiplying the amount paid.
Mystery symbols
Blank or question-mark symbols that all reveal the same randomly chosen symbol after the reels stop.
Symbol upgrades
A feature that turns lower-paying symbols into higher-paying ones, or removes low symbols, for the rest of a spin or bonus.
Bonus rounds
Free spins
A bonus round of spins played at no extra cost, usually triggered by scatter symbols and often with extra features.
Hold and win
A respin bonus where cash or coin symbols lock in place and each new one resets a counter, usually three respins.
Money collect
A mechanic where cash-value symbols pay out when a collector symbol lands, gathering all their values at once.
Pick bonus
A bonus round where you choose from hidden items on screen to reveal prizes, multipliers or the end of the round.
Wheel bonus
A bonus round where a prize wheel is spun to award a cash prize, multiplier, feature or jackpot.