Casumo’s ultimate online slots ‘how-to’ guide, from A-Z

How online slots work? Casumo explains the most common features!

Do you like the idea of playing online slots, but you’re not sure how they work? No problem, look no further, we got exactly what you need! Proudly presenting: The Casumo Online Slots Guide, where you will find everything you need to know about the most common game features and terms used in online slots. To make it even easier for you, we’ve listed them dictionary style, from A-Z. Go ahead and bookmark this page, it will help you understand how to play online slots and to discover your favourites.

Let’s start off with a great little tip: The best way to discover the features of an online slot and to help you understand the slot’s mechanic is to play around with it for a bit in Demo Mode, a free version of the game itself. You can discover its features and understand the mechanics before you start playing with real money. You can try most of the slots in our casino for fun without the need to be logged in to your Casumo account.

Now let’s dive into our ultimate online slots guide!

Casumo’s Ultimate Online Slots Guide

243 Ways-to-win

In 243 ways-to-win slots, certain combinations of matching symbols could be a win, provided that they appear anywhere on the adjacent reels, starting from the first and going left-to-right. There are no paylines in the traditional sense, but there are 243 ways to create a winning combination. Immortal Romance is an example of a 243 ways-to-win slot.

Immortal Romance gameplay screenshot

1024 Ways-to-win

1024 ways to win slots are set-up so that you could win when identical symbols land next to each other on the reels. This means that they are not restricted by the paylines that are available within the game, thereby increasing opportunity to possibly hit winning combinations across the reels. Gorilla Kingdom is an example of a 1024 ways-to-win slot.

Gorilla Kingdom gameplay screenshot

Autoplay / Autospin

A feature that allows you to set a predetermined number of spins under a certain bet level. The reels will spin continuously for that specific time.

Avalanche Feature

Also referred to as Tumbling Reels or Cascading Reels. This is a relatively new (and extremely popular!) feature in online slots. When you hit a winning combination, the winning symbols will “explode” and disappear, thereby freeing up space for new symbols to drop down into their place that could potentially trigger another win. Gonzo’s Quest and Viking Runecraft are two examples of cascading slots.

Gonzos Quest Megaways gameplay screenshot

Base Game

The base game is the main game in online video slots that serves as the “gateway” to a variety of extra features. There are usually a number of triggers to activate bonus features within the base game of an online slot.

Branded Slots

Online slots based on popular franchises such as popular TV series, movies, arcade games or books. See ‘Themed Slots’ for more.


The amount of money wagered on a spin. Also referred to as wager or stake.

Bonus Feature

The Bonus features of a slot game are extra rounds that have different rules than the ones from the base game and usually offer higher payouts. It depends entirely on the game that you’re playing when and by what a Bonus feature will get triggered and what the rewards are like. Sometimes you’ll earn free spins, others might give you extra cash or multipliers.

Cascading Reels

See ‘Avalanche Feature’.


In the past, slot machines were played with actual coins, but nowadays this is not overly practical – especially online. However, most slot machines still allow you to measure your wager in coins or credits.

Coin Value

Coin value and Bet Level both adjust how much you would like to play for per spin. Decreasing or increasing the dials will lower or higher your bet amount.

Colossal Symbols

Colossal symbols are symbol blocks of 2×2, 3×3, 4×4, 5×5, etc. which increases your chance to get a complete payline. It appears as an overlay anywhere on the reels and spins separately on top of the reels. Spinata Grande is a slot with Colossal Symbols.

spinata grande gameplay screenshot

Demo Mode

Demo Mode is the free play version of a slot game. This way you can give the game a try before you bet real money. You can understand the features and the mechanics and decide whether the game is of your liking or not.

Expanding Wilds

Expanding Wilds will expand and cover the entire reel. The more Wilds on a reel, the higher your winning chances. Starburst is a slot that features Expanding Wilds.

starburst gameplay screenshot

Free Spins

Free Spins are usually triggered by the combination of ‘Scatter symbols’, but it happens in other ways as well. During these Free Spins rounds, some more perks could possibly be given, which usually means bigger wins than during the classic gameplay in the base game.

Fruit Machine

Fruit Machine is the common name of slot machines in the UK, based on the fruit symbols that appeared on most slot machine models during the 1920s. Fast forward and the fruits have been polished, bejewelled, are being “warped” onto your screen and even sent to space! All the interesting upgrades take the traditional fruit machine experience to a next level. More on modern fruit slots right here.

Gamble Feature

Some slot machines give you the option to double or even triple your winnings – if you are willing to risk them, that is. The Gamble feature in most online slots is the equivalent of a coin toss. When you hit a winning combination on a particular spin, you get presented with the option to bet it on a 50/50 chance to either double it, or lose everything. Riches of Ra is a slot that offers the Gamble feature.

riches of ra slot gameplay screenshot

Grid Slot

Instead of reels, usually in a 3×3 or 3×5 format, a grid slot is just that: a grid consisting of symbols, from 5×5 up to 6×12. This type of slot doesn’t spin like usual slots, but the symbols fall down from the top of the grid instead, similar to Cascading Reels. Reactoonz is the perfect example of a grid slot.


Whilst playing slots you could ‘hit’ winning combinations (or even the Jackpot!), meaning that every win is a hit.


The Jackpot is the top prize of a slot machine. Ding-ding-ding! See more under Progressive Jackpot.


Lines or paylines are the “paths” that run across the reels, usually from left to right. Alignment of identical symbols on one or more (pay)lines will result in a win and the (pay)line is the row on which matching symbols should land to generate a win. Online slots can basically feature any number of (pay)lines. On most slots they’re fixed, though there are some that will allow you to select the number of (pay)lines you wish to play with as well as the amount you want to bet on each line.

Max Bet

The maximum bet you can place on a slot, with all paylines active and the highest possible coin denomination.

Min Bet

The minimal amount you can bet on the game. This can apply both to running a single payline, or placing the minimum line bet on all paylines. The minimum bet allows you to stretch your payroll for a maximum number of spins.


Megaways is an engine developed by the company Big Time Gaming. It’s a random reel modifier system that allows any spin you make to produce a different number of symbols across the reels, usually offering up to 117,649 ways to win. You can read a whole lot more about Megaways, right here.


Multiplier is a feature that is very common in traditional free spin features (such as 15 spins at x3 wins) and it’s often combined with Cascading reels as well. The multiplier simply multiplies your re-spin win, how many times depends on how many wins you manage to win in a row.


A nudge is a Bonus feature which would allow you to move the slot reels up or down.


See ‘Line(s)’.


The Paytable is a list of payouts on a slot machine. This shows you exactly how many coins or credits you will win for every combination of symbols.

Pick-me game

This is a type of Bonus feature where you’ll have to pick from several different options: some offer prizes, some take you to the next round for even bigger prizes, and others bring the feature to an end after you took your pick. The Rainbow Riches slot series all offer the Pick-me Bonus feature.

Progressive Jackpot

Progressive Jackpots aren’t fixed jackpot amounts, but they change over time instead. These slots usually have a slightly lower RTP in their base game, this is because it contributes to the Jackpot, and each bet placed on the slot contributes to building a progressive pot that constantly grows. If the slot machine is part of a linked progressive network, then all those slots contribute to the common jackpot. Hall of Gods is a popular Progressive Jackpot slot.

Hall of Gods gameplay screenshot

Random Wilds Feature

A Random Wilds feature means that regular Wilds could occur on the reels at any time of the game play.


The spinning columns on which the symbols are displayed / can appear. Online video slot machines can have any number of reels, though most of them are 3 reel and 5-reel ones.


The Re-spin feature lets you re-spin the reels on your next spin, helping you complete winning combinations. All of the other reels will be locked in their places. Re-spin comes in many variations, it’s often used with Sticky Wilds. Stickers is a slot known for its Re-spin feature.

stickers gameplay screenshot


Retriggering will give you additional spins to try and boost your winnings. This could happen when you’re inside an already won free spin feature. You would need for example 3 Scatters to retrigger the feature, depending on the game you’re playing.


The horizontal lines of symbols which you see in the slot’s screen. The numbers of rows will vary per slot game.


RTP (Return to Player) is an overall percentage that a slot game gives back to all its players. This percentage is usually anywhere between 94-98%, depending entirely on the slot that you’re playing.

Scatter Symbols

Scatters are symbols that usually trigger Bonus Games and Free Spins rounds from within the base game. A certain number of ‘Scatters’ will have to appear anywhere (or in a certain pattern) on the reels for bonus features to be activated. Scatters could result in payouts when they appear anywhere on the reels, outside of the fixed paylines and they will usually give you bigger payouts.


Each click on the button to start the game and get the reels rolling, is called a ‘Spin’.

Split Symbols

Split Symbols could occur on any reeled slots, but you’ll find them mostly on 5-reel, 3-row slots. With this feature, one of the reel’s symbols is divided into two or more icons. After spinning the reels, if the double picture stops alongside another identical symbol on any of the activated pay-lines, your winnings will increase accordingly as higher paying winning combinations are formed. Neon Rush Splitz is a slot that features Split Symbols.

neon rush gameplay screenshot

Stacked Wilds

Stacked Wilds means 2 or more Wild symbols appearing vertically ‘stacked’ on a reel, depending on which game it is, there’s the possibility of getting Stacked Wilds on every reel, while others have them appearing on specific reels. Flowers is a popular slot that features Stacked Wilds.

Sticky Wilds

The Sticky Wilds have the same properties as the regular Wilds, meaning that they will substitute any other symbol on any given reel. What is different though, is that they “stick” around. A Sticky symbol, once it has appeared, will remain at the same position on the same reel for a number of spins. Tower Quest is an example of a slot that features Sticky Wilds.

tower quest gameplay screenshot


Symbols are the little images that usually spin vertically. A symbol’s value varies, and usually the more rare it is, the higher the value.

Themed Slot

Online slots generally embrace a certain theme. It could be inspired by mythology just like Rise of Olympus, or music-themed like this Ozzy Osbourne game. Then there are tons of movie-themed slots, Jurassic World being one example, or slots based on a popular TV series such as Vikings. Depending on your personal likes and dislikes you could choose a slot based on its specific theme.

vikings gameplay screenshot

Tumbling Reels

See ‘Avalanche Feature’.

Variance / volatility

This basically measures the size of the winnings. Low volatility slots will give you lots of little payouts more often, whereas slot machines with high volatility work the other way around.

Video Slots

All of the slots that you can play from our online casino are referred to as online video slots. Video slots (usually) feature much better graphics, soundtracks and effects than their mechanical counterparts.


Wager is also referred to as bet or stake.

Walking Wilds

Walking Wilds progressively move to the side after every re-spin at no extra cost. They disappear from the reels after reaching the last reel. The Invisible Man is a slot that features Walking Wilds.

the invisible man slot gameplay screenshot


Regular Wild symbols replace most other symbols and make it easier to form winning combinations on the reels. The only symbol it doesn’t replace is the Scatter symbol.

Win both ways

This means that you could win by collecting identical symbols in a row from both left and right. Turning Totems is a slot with this type of win.

Win left to right

This is how most slots work, it means that you could win by collecting identical symbols in a row from left to right. Koi Princess is a slot with this type of win.


Classic slots used to feature only straight lines, but nowadays most online slots offer a much larger number of paylines. As a result, most paylines will run in zig-zag patterns across the reels.

Online slots, jackpot games and more at Casumo Casino

At Casumo we have a selection of 2000+ casino games to choose from, including jackpots, table games, a live casino and many different video slots. All you need to do to play at is register an account – if you haven’t already done so. Log in, first select Game Browser and then pick your favourite slot game.

18+ | Please gamble responsibly | T&Cs apply |