Slots by feature: what a mechanic actually changes

A feature is the part of a slot that has a name. Free spins, a bonus buy, tumbling reels, a fisherman who collects money symbols. It is what the studio puts on the promotional art and what most listing pages let you filter by, on the reasonable assumption that if you liked one game with tumbling reels you will like another.

What a feature does not tell you is how much the game returns. We have now read sixteen games, nearly all off their own rules screens, and the eight slots running the same collection mechanic state returns from 96.06% to 96.71%. That is a wider gap than exists between most of the mechanics on this page. A feature describes the shape of a session, which is worth knowing. It does not describe the price.

These are the mechanics we have read on a rules screen. A mechanic gets a section here once we have seen it stated in a game’s own rules, not once we have seen it mentioned somewhere.

• Free spins12 games read
• Scatter pays12 games read
• Multipliers14 games read
• Symbol collection8 games read
• Tumbling reels3 games read
• Cluster pays1 game read
• Megaways1 game read
• Bonus buy6 games read
• Ante bet6 games read

What a feature actually changes

Three things, and return to player is not one of them.

It changes how often something happens. Ten fixed lines paying left to right will pay small and often. A game that holds everything back for a free spins round pays nothing for long stretches and then pays properly. Both can return the same figure over a long enough run.

It changes how far a good round can go. Multipliers that combine with each other reach numbers that multipliers which merely add cannot. This is the one place where the mechanic and the maximum win are genuinely linked, and it is visible in the table further down: every game we have read with a ceiling above 20,000x runs tumbling reels and a multiplier that compounds.

It changes what you are allowed to spend. A bonus buy converts a long wait into a fixed price. An ante bet raises the stake on every spin in exchange for the round arriving sooner. Both are features in the sense that they appear on the rules screen, and both are decisions about money rather than about entertainment, which is why they sit at the bottom of this page rather than the top.

Mechanic by mechanic, with the figures

Each section below is what the games themselves state. Where only one or two games in our set carry a mechanic, the section says so rather than generalising from them.

Free spins

Twelve of the fourteen games have them, which makes this the least useful filter on any slots site. Free spins are not a feature so much as the default structure of a modern slot: the base game funds the round, the round pays.

What varies is what happens inside. Big Bass Christmas Bash retriggers up to four times and raises its collection multiplier at each step, so the round can grow while it runs. Eye of Horus awards a fixed batch and keeps its expanding wild for the duration. The name on the button is identical and the two rounds have almost nothing in common.

Scatter pays

Also twelve of fourteen, and for the same reason: a scatter symbol is what triggers the free spins round in nearly every game here. Two games use it as the whole paying structure rather than just the trigger. Sweet Bonanza pays anywhere on the grid for eight or more matching symbols with no lines at all, and Sugar Rush 1000 pays clusters of five or more that touch.

Multipliers

Twelve games say multipliers. We have read four different sums behind the word.

Adding and multiplying are not close to the same thing, and a filter that puts all four games under one tick box is hiding the only part that matters. This is the clearest example on the site of a feature label carrying almost no information.

Symbol collection

Eight games, the largest group we have read, and the mechanic that made Fishin’ Frenzy famous before Pragmatic Play built a family on it. A wild lands during free spins and takes the value of every money symbol on screen.

It is also the group that best demonstrates the point of this page. Eight games, one mechanic, and the following returns:

Two thirds of a percentage point separates the top of that table from the bottom, and the ceilings run from 2,100x to 10,000x without following the returns at all. Big Bass Halloween returns the least of the eight and stops at 2,100x. Big Bass Day at the Races returns one hundredth more and reaches nearly five times as far.

Tumbling reels

Winning symbols are removed and new ones fall into the gap, so one spin can pay several times. Three games in our set run it, and they sit unusually close together:

Eight hundredths of a percentage point covers all three. We would not claim a rule from three games, and we are not going to. What we will say is that tumbling is the mechanic that produces the two highest ceilings we have read, at 25,000x and above 21,100x, and that it does so because a tumbling sequence gives a compounding multiplier something to compound over.

Cluster pays

One game so far. Sugar Rush 1000 pays groups of five or more matching symbols that touch each other on a seven by seven grid, with no lines and no ways. One reading is not a finding, so the only thing this section can honestly say is what the game states.

Megaways

Also one game. Buffalo King Megaways states up to 200,704 ways to win, which is more than a standard Megaways game and comes from a sixth reel of its own. Its stated return, 96.52%, sits in the middle of everything else we have read, which is worth noting only because the ways figure is the largest number on the site by four orders of magnitude and changes nothing about the return.

Bonus buy

Six games state a price for the free spins round. In every one of the six, the return figure printed against the bought round is identical to the base game figure. Christmas Bash charges 100x the current total bet and states 96.71% for the base game and 96.71% for the bought round.

That is worth knowing in both directions. Buying does not quietly worsen the return in any game we have read. It also does not improve it, so what the price buys is time rather than value, and 100x total bet is a great deal of time to buy at once.

One detail almost nobody records: on the Big Bass games the two are mutually exclusive. Turn the ante bet on and the buy button is switched off.

Ante bet

Six games offer one. You raise the stake on every spin and the round arrives sooner. Christmas Bash charges 15x rather than 10x, so 50% more per spin. Buffalo King Megaways charges 25x rather than 20x, so 25% more, and states that the natural free spins rate is doubled in exchange.

This is the one feature we have caught changing the number at the top of the rules screen. Five of the six print a separate return figure for ante play, and two of those five print it below their own base figure:

A hundredth of a percentage point is small. The reason to record it is that it exists at all: two games from one studio, in one family, where paying 50% more per spin buys a marginally worse stated return rather than the same one. Nobody publishes that figure because nobody reads the second RTP line on the rules screen.

Every game against every mechanic

Reading down a column shows how common a mechanic is. Reading across a row shows what a game is made of. The empty cells are the honest part.

Game	Free spins	Scatter pays	Multipliers	Symbol collection	Tumbling reels	Cluster pays	Megaways	Bonus buy	Ante bet
Big Bass Amazon Xtreme	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	Bonus buy	Ante bet
Big Bass Christmas Bash	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	Bonus buy	Ante bet
Big Bass Day at the Races	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	Bonus buy	Ante bet
Big Bass Halloween	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	Bonus buy	Ante bet
Big Bass Vegas Double Down Deluxe	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	Bonus buy	Ante bet
Buffalo King Megaways	Free spins	Scatter pays	Multipliers	not read–	Tumbling reels	not read–	Megaways	not read–	Ante bet
Big Bass Splash	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	Bonus buy	not read–
Sugar Rush 1000	Free spins	Scatter pays	Multipliers	not read–	Tumbling reels	Cluster pays	not read–	not read–	not read–
Big Bass Bonanza	Free spins	Scatter pays	Multipliers	Symbol collection	not read–	not read–	not read–	not read–	not read–
Sweet Bonanza	Free spins	Scatter pays	Multipliers	not read–	Tumbling reels	not read–	not read–	not read–	not read–
Fishin' Frenzy	Free spins	Scatter pays	not read–	Symbol collection	not read–	not read–	not read–	not read–	not read–
Eye of Horus	Free spins	Scatter pays	not read–	not read–	not read–	not read–	not read–	not read–	not read–
Aviator	not read–	not read–	Multipliers	not read–	not read–	not read–	not read–	not read–	not read–
Big Bass Crash	not read–	not read–	Multipliers	not read–	not read–	not read–	not read–	not read–	not read–
Crazy Time	not read–	not read–	Multipliers	not read–	not read–	not read–	not read–	not read–	not read–
Spaceman	not read–	not read–	Multipliers	not read–	not read–	not read–	not read–	not read–	not read–

A dash there means we have not read that mechanic on that game. It is not a claim that the game lacks it. Big Bass Bonanza almost certainly offers a bonus buy, in the way that all of its siblings do, but its buy page was never captured and we are not going to tick a box on the strength of a family resemblance.

What a feature list cannot tell you

Four things, in descending order of how often they are got wrong.

How the multipliers combine. Covered above, and the single largest gap between what a filter says and what a game does.

How often the round arrives. No studio in our set publishes a hit frequency or an average number of spins between rounds. Volatility is offered as a proxy and it is a coarse one, which the numbers page goes into.

What the round is capped at. Maximum win applies to the whole free spins round on every Big Bass game we have read, not to a single spin. Christmas Bash states that if a round reaches 5,000x, it ends immediately and the remaining spins are forfeited. A ceiling is a stopping rule, not a target.

Whether the features can be combined. The ante bet and the bonus buy cannot, on any Big Bass game we have read. Two ticks in a filter, one of which switches the other off.

Browse another way

• Browse by featureMegaways, cluster pays, hold and win, bonus buy. How a game actually pays, rather than what it is dressed as.→
• Browse by the numbersRTP, volatility, maximum win and reel structure. The figures we read, sortable, with the gaps left visible.→
• Browse by studioWhat a company tends to do when it builds a game, and the RTP span we read across its catalogue.→
• Every game we have readThe full list, ordered by our score, with the demo attached where the studio allows it.→

Common questions

Does a bonus buy lower the RTP?

Not in any of the six games we have read. Each states a separate figure for the bought round and each states the same figure as the base game. Big Bass Vegas Double Down Deluxe prints four figures, for normal play, ante play, the bought round and the bought super round, and all four read 96.50%. Other studios may differ and we have not read them.

Which feature gives the biggest wins?

On the games read here, tumbling reels with a compounding multiplier. Sugar Rush 1000 caps at 25,000x and Sweet Bonanza above 21,100x, and both tumble. That is a statement about the ceiling, which is the most a round can pay before it is stopped, and not about what a session is likely to do.

Why is a mechanic missing from a game that clearly has it?

Because we have not read it on that game’s own rules screen yet. Every tick in the grid above corresponds to a screen we opened, and an untagged game is a reading we have not done rather than a feature the game lacks.

Are these features different at different casinos?

The mechanics are not. The stated return can be, because some studios ship more than one configuration of the same game and an operator chooses which one to run. That is a reason to check the rules screen of the game in front of you rather than to trust any listing page, this one included.