Online Slot Machines have come a long way since the traditional 3-reel fruit machines first became popular in casinos, pubs and clubs all over the world.

These games are operated by various software providers and play out more like a video game, without the restrictions of three mechanical reels. Game developers have continued to push boundaries over the years, creating games with five or more reels, hundreds of paylines, complex features and bonus rounds, and high-quality video and 3D graphics.

This change has led to the development of a diverse variety of online slots, with increasingly complex feature rounds and bonus games. Regular players look for the most engaging games and features, and there is a real battle among developers to come up with new, innovative ideas to keep customers interested and coming back to play their games.

For the uninitiated, however, the range of machines can be overwhelming, and features can be difficult to understand. We’ve put together a brief guide to the features regularly found on online slots, with detailed descriptions of each when you click on the feature.

Bonus Games

Bonus games come in a variety of forms, and give you a chance to win extra money by playing the feature game. Bonus games are usually awarded if you line up certain symbols on the reels, and last for a short period before you are returned to the main game. Some bonus games feature complex video graphics, while others are much simpler. Some require an element of skill, while others are completely random. This is where online slots really come into their own and cross over into video games, and many of the features we’ve seen involve complex storylines and gameplay.

Cascading Reels

Cascading Reels bring a unique and alternative appearance to how slot games work. Instead of a standard set of spinning reels, the icons included within the game fall, or cascade down to make room for a new selection, and what’s more, any wins will also cascade down or disappear, allowing further icons to cascade down and fill the empty slots!


What would a slot machine be without coins? Well, it wouldn’t be the kind of game genre that it’s become today, that’s for sure. Coins are what make a slot machine a slot machine. From the land-based casino slot machines to online games, the coins and coin values allow avid players to place their wagers, and do so at an amount of their own preference.

Expanding Wilds

Playing slot games is very much about the extra added features that it provides these days, as well as the inclusive graphics, themes and standard game play. One of the several added perks that online video slots offer up today is expanding wilds – a truly stretched treat of a wild icon that spreads out across a whole reel to turn it entirely wild in itself.

Free Spin Rounds

Free spin rounds are a bonus feature which, as the name suggest, provides you with a number of free spins to boost your winnings. A free spins round can be triggered in a variety of ways, such as when certain symbols line up in a row on one of the reels. You will be awarded a certain amount of spins (depending on the game), and any winnings will stack up as you watch the spins revolve around the reels. This is one of the simplest and most common bonus rounds found on slot games.

Gamble features

The gamble feature is a throwback to the fruit machines of old, where it was a popular bonus game. It offers players the chance to ‘gamble’ their winnings, which are usually doubled if you win, but will be lost if you lose. Common gamble buttons require a player to predict the colour of the next card to be drawn from a pack, or to predict whether the next card will be higher or lower than the previous one.


If you’re ever playing your favourite slot product and you manage to activate the freespins round that is included, you’ll know how thrilling a round that is. Well, retriggering just adds to the excitement, providing you with additional spins to try and boost your winnings! What could be better than claiming something for free, and then managing to claim extra freebies on top?


How do you find your favourite slot game online? Do you play products from a specific developer? Or games with a specific theme to them? Perhaps you look for bonus features and begin playing? Well, there are some people out there who take advantage of a game with a high Return to Player (RTP) rate, and taking it into account when selecting which one to play isn’t too bad a strategy.

Scatter Symbols

The general rule of slot machines is that you have to line up certain symbols on a payline to get a win. This rule doesn’t apply to scatter symbols, which is why they’re sometimes called a slot player’s best friend. They can appear in any position on any reel and reward you with a win, or open up a bonus feature such as a free spins round. They are usually one of the highest-paying symbols, and are often represented by a symbol that reflects the overall theme of the slot machine.

Sticky Wilds

It’s very easy to find an online slot game that features wild symbols these days. In fact, there’s more of them included in products than any other special feature. On top of the standard sort though, sticky wilds have also become a lot more prominent in the world of online slots, providing an icon that stays in its place for a single or more re-spins of the reels, enabling players to take advantage of the opportunity to win big

Transferring Wilds

If you’ve ever played a game and wished that a symbol could move from one place to another to assist you with a win, look no farther than a game which includes transferring wilds. These variations on the standard icon will transfer themselves from one reel set to another, allowing you stronger chances of being able to pick up one or more winning combinations in the process. A perfect development

Tumbling Reels

If you’re a fan of slot games, but also require them to have something a little extra incorporated into their game play, look no further than a product that has been designed with tumbling reels. These work in much the same way as the standard ones, but once a win has been crafted, any symbols included will vanish to make room for several more. A genius way to provide yourself with extra winnings

Wild Symbols

Wild symbols work in the same way as a joker in a deck of cards – they can substitute for any other symbol to complete a winning line. So if you have four matching symbols and a wild symbol along a five-reel payline, you are paid out as if you had five matching symbols. Slots developers have experimented with various different ways of using wild symbols in their games, and they now come in several forms, including expanding wilds, shifting wilds, sticky wilds, cascading wilds, and stacked wilds.

Multiplier Symbols

As the name suggests, multiplier symbols will multiply your winnings by a certain amount. This can range from an X2 multiplier up to X100 and X1000 multipliers depending on the game. They also come in various forms, with some operating on the normal reels, while others are only part of a certain feature or bonus game.

Ways to Win

Some video slots have been developed with hundreds of different ways to win across the reels, without necessarily hitting traditional win lines. These slots are generally referred to as 243 or 1024 ways to win slots (depending, of course on the number of ways to win). Rather than the traditional straight paylines from right to left, these slots will pay out on combinations from left to right, no matter where the matching symbols appear on each reel.

Win both ways

Win both ways is not something to be taken lightly. In fact, it’s something to scream and shout about, as whenever it’s included in a slot game, it provides nothing but splendour. If you’re able to claim wins from left to right, then you should also be able to grab them from the opposite direction as well, and with this particular feature activated, you’ll be able to do just that


The payline is the row upon which matching symbols must land to generate a win. On traditional three-reel slots, the single payline is the central row along the three reels. Video slots with five or seven reels can feature any number of paylines, with some like those described above, incorporating thousands of paylines. Your stake for each spin of the reels is split between paylines, so if you are playing a 20 payline slot your stake will be 1 unit per payline. Most slot machines allow you to select the number of paylines you wish to play, and the amount you wish to bet on each line.

Pay Tables

The pay table is usually accessible from the main game screen of an online slot, and will provide information about the game, the scatter and wild symbols, the payouts for winning combinations, and details of how bonus games are accessed. Clicking on the pay table will open up a window with this information, and it’s worth having a look before you start playing to enhance your understanding and enjoyment of the game.

Progressive Jackpots

Progressive jackpots have always been popular in bricks and mortar casinos, and they work by linking a group of slot machines together to pool a very large jackpot. Any single player on any one of the machines could get lucky and scoop a life-changing amount of money. The internet has made it very easy to network slot machines online, and progressive jackpots are hugely popular amongst players.

Themed Slots

Traditional fruit machines featured bells and fruit or similar symbols to create winning combinations, but themed slots have become much more prominent over the years in land-based and online casinos. There is huge variety out there, with slots based on popular TV shows like Wheel of Fortune, movie franchises like Batman and Spiderman, iconic bands such as Kiss and Guns N’ Roses, and a vast array of other themes. These games tend to be more engrossing because you are familiar with the characters/symbols and storylines.


Volatility isn’t a feature of a slot machine as such, but it is very important to the way you play slots. Generally, high-volatility slots give you less wins but when they do pay out they tend to be big wins; low volatility slots pay out much more often, but these tend to consist of lots of very small wins with just an occasional big win. Low volatility slots are good for players with a limited budget, as they will pay out little and often to keep your bankroll ticking over.

Click on the link to each feature for a more detailed description of what it is and how it works. If you’re ready to start playing online slots, have a look at our casino reviews, slots reviews, and bonus pages to find the best places to play, the best games to play, and the best sign-up offers for new customers.