Online Slot Reviews

Where do we start when it comes to the topic of online slots? Online slots are, by far and wide, one of the most played types of games at online casinos and slot sites. Over the years, many casino game studios have produced thousands of online slots, and it has to be said - they have come a long way from their humble beginnings. As a slots review guide, we have played countless online slots over the years. Some have impressed us with top-grade graphics and fun in-game features - even wins (and plenty of losses). A large part of what we do here is review online slots - below, you'll find all of our genuine online slot reviews to give you more details about each game - especially new online slots!

Online Slots - Time Line

Below, we're carrying on the answer our own question at the top of this page; we're going to start at the beginning of online slots and take on through the years to where online slots are today. That way, we should give you an in-depth guide into the many types of slots you'll find online so nothing becomes too mind-boggling when you're next logged into your casino account, dumbfounded on where to start or what to play next. This online slots guide takes the complexity and confusion out of the jargon.

Slot Machines To Online Slots

We can thank Charles August Fey for the real money online slots that we can play in abundance today. Bavarian-born American Inventor Charles didn't invent the online slot- that was way before his time, but he was one of the pioneers to create the slot machine in its earliest days.

However, we must also thank Sittman and Pitt of Brooklyn, New York, who developed a gambling machine in 1891 that was a precursor to the modern slot machine and Feys' creations. Their gambling machine contained five drums holding 50 card faces and was based on poker. Players would insert a nickel and pull a lever, which would spin the 'drums' and the cards they held - and the player would hope for a good poker hand outcome.

The downside to Sittman and Pitt's creation was that there was no direct payout mechanism. So a pair of kings might get the winner a free beer, or a royal flush could pay out cigars or other drinks, but the prizes were wholly conditional upon what the establishment offered. Because of the vast number of possible wins in the original poker-based game, it proved virtually impossible to make a machine capable of awarding an automatic payout for all possible winning combinations.

Charley Fey & The Liberty Bell

However, Charles Fey of San Francisco, California, devised a much simpler automatic payout mechanism not long after. In 1894, mechanic Charles introduced the first coin-operated slot machine to bemused punters in San Fransico. The following year, Fey built the iconic 4-11-44 machine in his basement. It proved to be very successful at a local saloon, and he soon became inspired to quit his job and work on the idea full-time. And with that, he opened a factory to produce more units on order.

In 1898, Fey built the Card Bell slot machine, which was the first ever three-reel slot machine that offered automatic cash payouts. The Card Bell slot machine was designed with a handle (lever) that, once pulled downward, set the reels spinning until they stopped. Playing card suit marks lined up to form poker hands and hopefully a winning combination.

Charles Fey's next slot machine, called the Liberty Bell, was built in 1899 and, this time, used horseshoes and bells as well as playing card suit marks on the reels. Three bells lined up in a row on the reels meant the players would be awarded the top payout. The Liberty Bell proved extremely popular among saloon customers in San Francisco and was by large copied by Fey's competitors, including the Mills Novelty Company of Chicago.

Unfortunately, approximately only 4 Liberty Bell slot machines built by Fey survive today. The main reason for this travesty is due to the 1906 San Fransisco earthquake. One of the first-made Liberty Bell slot machines is preserved as a historical artefact in the Nevada State Museum (so it's possible to see such a historical casino relic in person - especially if you happen to be in Las Vegas!). Furthermore, a plaque was placed at 406 Market Street in San Fransisco, where Charles Fey's Workshop was located, and where the Liberty Bell Slot machine was invented.

Land-based slot machines soon took off across the states and the globe. Before their invention, casinos offered limited games such as card games like poker and blackjack with croupiers. Hence, the Liberty Bell presents a significant milestone in the evolution of gambling technology.

Real Money Online Slots - The First Generation Online Slots

Slot machines made another iconic jump from land-based casinos to online casino sites when the first online casino was launched by Microgaming in 1994. That may sound very early and pre-internet, but it wasn't. Before online casinos, Microgaming, an Isle of Man-based software company, developed the first fully functional gambling software, secured with security software developed by CryptoLogic. Safe transactions soon became viable, leading to the first online casino in 1994, called InterCasino.

"What was the first ever online slot?" is a difficult question to answer at this stage. Believe it or not. Different sources and software companies have different views on the subject. There is a somewhat lack of historical information. However, if we know that Microgaming was the company that launched the first-ever online casino, and Microgaming has always made its own online slots, we're going to hazard a guess that a first-generation Microgaming slot was among the first-ever slots online.

Online Slots In 2024

Roll on a few decades, and online slots have come a long way. At online casinos and slot sites, customers are spoiled for choice. Microgaming may have been the first slots software company, but today, there are over 200 and counting. The first online casinos would usually offer games from one sole software provider - and today, online casinos are trying to work with as many as possible. Most online casinos and slot sites have at least 50 different software providers integrated into their systems. The result is to offer over a staggering 3,000+ online slots for real money. We wonder what Carles Fey or Sittman & Pitt would think if they saw what their vision and inventions have become in the 21st century? They probably wouldn't believe their eyes!

There may be thousands of online slots, but they are not all the same. As the years have passed, slot game developers have become savvier, more daring, more controversial, risk-taking, and inventive to thrill their players for the best possible entertainment. Let's look at the different types of online slots and their mechanisms you're likely to encounter at new slot sites and online casinos. We cover the most basic to the most complex so you know what to look out for:

Classic Slots/ Retro Slots/ Vintage Online Slots

Classic slots are the online version of slot games most similar to 3 reel slot machines and fruit machines (also called one-armed bandits and online pokies in Australia and New Zealand). Classic slots, often called Retro slots, are still available at all online casinos and slot sites because they still have a considerable following. Probably because of the nostalgia factor of a much simpler time, classic slots are popular because they are simple and easy to follow - which are the main draws for playing them.

Vintage slots have basic/fewer rules, and you'll get the hang of them quickly. With classic slots, there's no need to try to understand complex side features or new reel designs that can often make no sense - with the classics, you just load up and spin and watch the reels stop!

A few iconic land-based classic slot machines can be found online for players searching for legendary games from the golden days. Such games include Sizzling Hot Deluxe, Rainbow Riches, Wolf Run, Siberian Storm and Book of Ra. The online versions look and work the same; they've been fully digitalised for access any time and anywhere.

Progressive Jackpot Slots

Much like land-based casinos, online casinos also have progressive jackpots. Progressive jackpot slots are games that offer a 'pooled' jackpot, which increases incrementally every time a wager is placed on it. The jackpot amount continues to grow before a lucky player wins it. From then, the jackpot will reset and grow over time until it's won, and the cycle begins again.

One of the first online jackpot slot games was called 'Cash Splash', another Microgaming creation. CashSplash has been responsible for some of the biggest jackpot payouts ever. Microgaming has launched many other progressive games since then, including the infamous Mega Moolah series of games and their Wowpot jackpot slots (see below for more information on those). It did not take long before other providers launched more progressive jackpot games either. Netent made its mark on the topic with Mega Fortune and Mega Fortune Dreams to rival (at the time) Mega Moolah Slots.

IGT brought their iconic jackpots from offline to online, with Siberian Storm and Cleopatra Mega Jackpots being just some of their mega hits. Not all new slot sites offer progressive jackpot slots, though. There is an extra cost involved (and more financial risk) for casinos to offer progressive jackpot games, so not all operators choose to offer them all, or any, especially the newer brands trying to break into the market share - they use that budget elsewhere.

Wowpot Jackpot Slots

On the progressive jackpot subject - Wowpot slots are a relatively new (well, in the grand scheme of things) type of online slot, again from slot innovators Microgaming. WowPot series consists of games with substantial progressive jackpot pools, seeded at a cool £2 Million (this means that each jackpot starts at £2 Million - it's guaranteed).

WowPot progressive jackpot works more or less like any other progressive jackpot network. The jackpot series includes a handful of slots, including Sisters of Oz WowPot, Well of Wishes WowPot, 9 Blazin' Diamonds WowPot, Sherlock and Moriarty WowPot and Queen of Alexandria WowPot.

Keen gamblers may remember that Microgaming had a similar progressive jackpot network in its classical slots (namely Mega Moolah, CashaPillar and CashSplash); however, WowPot progressive slots replaced the previous jackpot network with its multi-tier jackpot system. The Wowpot progressive network includes four different jackpot tiers:

1. Mini Jackpot: Seeds at £10
2. Minor Jackpot: Seeds at £100
3. Major Jackpot: Seeds at £50,000
4. Mega or Wowpot Jackpots: Seeds at £2 million
5. Megaways Slots

Megaways slots are a newer phenomenon and an exciting way for players to experience online slots. You may have already come across various Megaways games - there are hundreds of them now, and they're available at almost all new slot sites and online casinos. Megaways slots are the invention of Australian slot game pioneers Big Time Gaming. Megaways slots come with a never-seen-before innovative reel mechanic offering 243 to 117,649 ways to win on each spin. Every spin is unique, and the number of pay lines changes on every spin, with the idea of giving you plenty of chances to land the wins.

Not all Megaways online slots are from Big Time Gaming; slot game companies may use the Megaways license and produce their own games. The most notable Megaways slot games include Rainbow Riches Megaways, Twin Spin Megaways, Bonanza Megaways, Monopoly Megaways, Anubis Wild Megaways, Buffalo Rising Megaways and Fishin' Frenzy Megaways.

Most popular and iconic online slots now have their own Megaways versions, and new slots often are made into Megaways editions first due to the overall popularity of Megaways slots. Most of the time, Megaways slots offer average to slightly higher than average RTP. The Megaways slot that offers the highest RTP % is Medusa Megaways, which has a juicy 97.63% RTP!

Link&Win Online Slots

Link&Win is a unique mechanic that's another innovative creation from Microgaming. Link&Win slots are similar to Pragmatic Play's Hold and Spin slots in the sense that it's a respin feature that resets with every coin that lands, but Microgamings Link & Win mechanic has a little more pizazz to it.

The Link & Win feature is basically a respin feature that resets each time you land a designated symbol. Link&Wins can be triggered by landing 6 to 14 special Link&Win symbols on the screen in any position. Each symbol has a certain amount of prize denoted to it, which is totalled together at the end of the feature and then awarded to the player.

Microgaming tends to release one Link& Win new slot game every month or 2. Some of the most popular Link & Win online slots include Game of Thrones Link&Win, Thunderstruck Wild Lightning Link & Win, Hyper Gold Link & Win and Star Fever Link & Win. You can find Link& Win slots online at any slot site that has chosen to add Microgaming slots to its game library.

Slingo Slots Online

Slingo slots are a hybrid of slots and bingo games, but we thought such a fun game deserved a mention on this page. Slingo is a version of an online slot game that combines (the best) elements of online slots and online bingo. Slingo was first created by New Jersey real estate developer Sal Falciglia Sr. in 1994, who founded the company Slingo, Inc. to develop and market games based on the Slingo theme. Today, Gaming Realms PLC owns the rights to make and distribute Slingo games to online gambling sites and has released over 50 award-winning games, often partnering up with other gaming companies to make Slingo versions of iconic slots.

Standout Slingo games include Lucky Larry's Lobstermania Slingo, Da Vinci's Diamonds Slingo (collaboration with IGT), Rainbow Riches Slingo (collaboration with Light & Wonder), Slingo Fluffy Favourites, Slingo Britains Got Talent, Slingo Super Spin, Who Wants To Be A Millionaire Slingo and Shark Week Slingo.

Slingo games are not available at all new slot sites; however, many leading casinos opt to offer their games due to their popularity. You can find the best Slingo sites here.

Must Drop Jackpot Slots (Also Known As Must Fall Jackpot Slots)

Must Drop Jackpot games from Red Tiger Gaming offer a unique mechanic within that enables progressive jackpots to be awarded more frequently - meaning jackpot prizes are guaranteed to drop at some point within a time frame. Must Drop Jackpot online slots can payout the jackpot prize pool daily and hourly. More often than not, hourly and daily prizes will be included in a single game.

The daily jackpot prize is typically higher than the hourly as it is won less frequently and has more time to increase and grow bigger. The consistent feature of Must Drop Jackpots is the fact that jackpots will drop in a certain amount of time. This feature is the main draw of players because they know that a jackpot will fall during a period of time. Other progressive games, such as Wowpot Jackpots, usually drop every couple of months - with a much larger jackpot, yes, but with Must Drop Jackpots, it can be exciting knowing that a progressive jackpot win is only a minute or hours away when playing.

Must Drop Jackpot games usually offer multiple prizes, all of which can be viewed via the in-game menu. The menu will provide you with information on the game's rules, paytables, frequency of jackpot drop/fall and any other additional bonus features.

Unconventional Payout Structure Online Slots

Casino game studios should be inventive and create never-seen or experienced-before-seen slots to stay relevant and one step ahead. NetEnt is one such game provider that was first with their "Avalanche Reels" (where reels "fall away" and new ones drop into view), which were a massive hit for the time. Again, in 2020, they blew people's minds when they introduced the INFINIREELS™ mechanic. It was used for the first time in Gods of Gold: INFINIREELS™ slot, which takes players on an outlandish reel adventure in the Kingdom of Mesopotamia. As players start spinning the reels, they will begin with a standard 3×3 reel set-up, but as the game goes on, the reel configuration will change as the reels can grow infinitely.

Yggdrasil has also wowed the crowds with its Gigablox mechanism. When a mystery symbol loads on the reels, it will reveal between 3 and 9 symbols of the same kind, thus creating 2×2, 3×3, 4×4, or 5×5 sized slot symbols. Another mechanic to watch out for is 'Cluster Pays' slots from Netent, a unique type of slot where winning combinations are activated within clusters. NetEnt first introduced this feature with the Hawaain-themed online slot called Aloha! Cluster Pays. Cluster Pays slots generally eliminate the conventional payline mechanism of left to right and vice versa.

High Payout Slots

Slots can also be classified depending on their RTP % (return to player rate/percentage). A slot RTP % is used by game studios to indicate how much the particular slot will pay back to players over time. The value is expressed using percentages. Usually, you can find this information in the game paytable. It's essential to mention that the RTP does not denote what one player will win back during their own personal gaming session - it's a figure calculated on average across millions of spins. The % figure is designed to show you how much it will pay back and the house edge.

Typically, the RTP of slot machines at land-based casinos is between 80% and 90%, which is average and understandable as the land casino has less profit margin and more overheads than what an online casino has. Most online slots have an RTP of around 96%, so as you can see - the RTP is much higher when you play online slots. Looking for the highest RTP slots will give you a greater chance of winning because the slot pays back more overall. But remember, all outcomes when playing slots online are still entirely random.

Themed Slots

Every single online slot game has a theme; it could simply be a classic slot theme or something more detailed, like a movie-themed slot. A game's design and appearance can significantly impact how people choose and play a slot game. Themed slots add a familiar touch to gameplay with well-known narratives and customised features. Certain themed slots go the extra mile, too. For example, movie-themed slots such as Jurassic Park or Game of Thrones often feature footage and soundtracks from the movie itself, making the experience all the more engaging - especially if you're a fan!

New themed online slots are often released at the same time with new movie or TV releases, new album launches, and also certain holidays during the year, so, as you can imagine, if you're looking for a specific theme, the chances are that you'll find a slot based on it.

Many popular themes include Egyptian themes slots, Sweets/Candy themed slots, Horror themed slots such as Halloween/Ghosts, Christmas-themed slots, Easter-themed slots, Viking-themed slots, Luck of The Irish themed slots, TV-themed slots, Asian-themed slots - the list could quite literally go on!

Branded Online Slots

Similar to themed slots above, branded online slots have become more and more common, with online slot providers like NetEnt, Microgaming and Playtech offering a wide range of online slots, which are the official titles of popular movies/films, television shows and musicians/rock bands.

Some examples of top branded movie/TV online slots include Hells Kitchen Slot, Rocky Slot, Game of Thrones Slot, Goonies Return Slot, Street Fighter 2 Slot, Jurassic Park Slot, Terminator 2 Slot, Bridesmaids Slot, and I'm A Celebrity, Get Me Out of Here Slot. Top music branded online slots include Alice Cooper and The Tome of Madness, Guns N Roses Slot, MotorHead Slot, Rex Nex Cotton Eyed Joe Slot, ZZ Top Slot and N Sync Pop slot.

Online Slots - Round-Up

We told you at the start of this online slots article that there was quite a lot to cover - we weren't wrong! We could have kept going, but hopefully, you now see that there are online slots for every occasion. The best way to learn what they're all about is to play them. You don't always have to play for real money either - many online slots have free demo games at online slot sites where you can play for fun. You will most likely have to create an account to play for free (due to rules and legislation from the UK Gambling Commission), but playing demo games is a great way to try before you buy.