Our Review of the Best Online Slots of All Time - Full 2024 Guide

Our Review of the Best Online Slots of All Time - Full 2024 Guide

Online slots are, without a doubt, some of the most popular games on the internet. When it comes to online casinos, they’re the most played types of games in the industry. That also means that there are literally thousands of them, and the total number of slot games keeps growing by the day. It doesn’t seem to be slowing down, either – the biggest companies in the world keep pumping out fantastic online slots as time goes by. Some of these games have managed to reach cult status and transcended the traditional games of the industry, which has allowed them to become loved by hundreds of players from all over the world. Some games have been responsible for giving out amazing rewards that have changed the lives of thousands across all continents of Earth. Today, we aim to review the world’s most important and best online slots of all time. There are a handful of games that we want to mention, so let’s get down to business!

The Best Online Slots Ranked

We have compiled six of the best online slots in the industry, all of which stand as some of the most influential titles ever created. These games have not only revolutionized the world of online slots, but the entire iGaming industry as a whole. These games are all world-class, and we want you to play them as soon as possible. We’ll keep our reviews short to help you get down to business quickly!


Starburst is a unique game and a phenomenon of the industry. This online slot has been played so many times that it has quickly become the most played online slot in the iGaming world, with it being part of dozens of online casino promotions from all across the world. Many online casinos offer free spin bonuses to spend on Starburst, so it’s no surprise that the game is so popular. As it is tradition with most NetEnt games, Starburst has an RTP of 96%. The Wild feature of the game can only be triggered in the middle reels (2, 3, and 4). Being a 5-reel game, it aims to keep things simple for the player to understand what is going on all the time. The game, however, shines by offering players a lot of features that are very easy to understand, making this game one of the best beginner slots of all time. That’s one of the reasons why it has managed to amass such a large cult following!  

Book of Dead

Book of Dead growth in popularity in recent years is what has managed to make this game stand at the top and keep Book of Ra Deluxe further down in our list of the best slots of all time. It’s basically a better version of the classic Book of Ra slot, with much better graphics and gameplay features that make the game far more entertaining to play. One of the reasons why so many players love Book of Dead is that it provides you with the chance to win 5,000 times the amount of your stake with a single bet, provided that you’re looking enough with your spins, of course. It also comes with a solid 96.21% RTP, which allows players to make a good profit even on a not-so-lucky day. Accompany Rich Wilde in his adventure to uncover the secrets of this Egyptian tomb and win rewards worthy of an ancient pharaoh!  

Mega Moolah – The Best Progressive Jackpot Slot

Mega Moolah is the world’s most popular progressive jackpot slot, providing players with the chance to win a minimum jackpot of €1,000,000. However, players have been known to win much higher jackpots than that one. Some lucky Mega Moolah players have won up to €16,000,000 in rewards, making it the highest-paying online slot of all time. The catch is that players tend to lose a lot of money, on average, while playing this game. It has an RTP of 88.12%, which explains this phenomenon. The jackpot wheel that enables you to access the major jackpot of the game will trigger randomly at any point when you’re playing the game, so it does keep you coming back for more every time. In any case, Mega Moolah provides players with the chance to win some of the biggest rewards on the internet. If you’re a jackpot hunter, then Mega Moolah is the slot that you’ll want to play. It’s not all about the major jackpot, either. You can also claim smaller jackpots that don’t require the same level of luck that you need to claim the ultimate prize. Mega Moolah is the world’s best progressive online slot. Give it a go if you’re after crazy rewards.  

Gonzo’s Quest

This game will take you on a fantastic quest where you’ll be joining Gonzo to find the hidden city of El Dorado, where a world of fantastic rewards is there for the taking. Some online casinos even come with a VR version of this game, which enables you to take your experience to the next level! In any case, Gonzo’s Quest is an easygoing title that allows you to win rewards worth2,500 times your stake with its basic spin feature, or up to 37,000 times thanks to the free spins and multipliers. With an RTP of 95.97%, Gonzo’s Quest comes with everything you need to have in an online casino game that promises large rewards and fantastic bonuses. The game features the Avalanche mechanic, which means that one spin could get you playing for a long time. Whenever you connect symbols, they will break and new symbols will come down. This is a doorway to a world of crazy multipliers, all waiting for you at the Amazon jungle alongside Gonzo.  

Thunderstruck II

Thunderstruck II will take you on a wild ride and place you among ancient gods as you try to claim the ultimate prize of the game – 2.4 million coins! Thunderstruck II is one of Microgaming’s best online slots, as well as one of the most played games in the world of iGaming. It’s fully based on ThunderstruckI, but it does have much better graphics and the gameplay feels more fluid. It does still present similar symbols, such as Odin, Thor, Loki, Valkyries, and the reinvigorated Stormy bonuses. The Loki symbol could get you extra free spins; Valkyries can reward you 10 free spins and a multiplier of 5 times the amount of your stake, and the rolling reels feature could propel your winnings through the skies and into Valhalla.  

Book of Ra Deluxe

Book of Ra was made famous in Las Vegas, but it quickly made its way to the world of iGaming. It has a basic setup of 5 reels and 3 rows. It is an ideal game for high rollers, though. You can bet anything from 10 cents per spin up to €400, which makes it one of the most lucrative and profitable online slots on this list. Book of Ra was also the inspiration to many of the games that came after it, and the Book of Ra Deluxe edition is just an ode to that influence. The game can reward you with up to 500 times your stake, but the graphics and Egyptian-themed gameplay alone makes it one of the finest online slots that you can play in the industry.  

What are Online Slots?

Online slots are games where the only objective for the player is to press the spin button until a bonus round is unlocked, or until the player is satisfied with the time that they’ve spent playing the game. Online slots don’t require a lot of previous knowledge to get into, which makes them far more popular than other games like blackjack where you do need to have a notion of what you’re doing to win.

One of the reasons as to why online slots are so popular is exactly because of this ability for any player to enjoy these games. You don't need to learn how to trick an online slot machine - the games are designed in a way that allows players to win with some luck.

You don’t need to be an expert of any sort – all you need to do is spin the reels and rely on your luck. With that said, each online slot comes with different features as well as diverse layouts. Some are harder to understand than others, but all of them provide you with the chance to win with no prior knowledge of what you’re doing.

Top Slot Creators

There are dozens of companies that create online slots and provide them to the best online casinos in the world. However, there is a handful of companies that shine above all of the rest, which has earned them the reputation of being the best in the industry. Here, we’ve ranked the most important casino developers in the world and provided you with a small review of each one of them.

Net Entertainment (NetEnt)

NetEnt is, alongside Microgaming, the biggest online developer of slots in the industry. The company shines by producing some of the most popular games on the planet, many of which you’ve already read about on this list. However, it’s not all about big numbers for NetEnt. The company is also known for creating games with world-class graphics, a fantastic set of sound features, and fantastic bonus rounds that players can activate with relative frequency.


Microgaming is the biggest competitor of Net Entertainment. These companies have a rivalry that has served to make both of them create some absolutely world-class games, in hopes of each company overcoming its counterpart. Microgaming also focuses on creating fast-paced online slots, which means that their games are often far quicker to play than those you find at a NetEnt Casino. In any case, Microgaming has also created a ton of titles that shine above the rest, including the most played jackpot slot of all time – Mega Moolah.


Playtech is a very prominent online casino game developer, with some of the best games in the industry being developed by the company. They specialize in providing players with high-quality games that come packed with free spins and special in-game bonuses, which keep players extremely hooked to each title and make every single game feel as unique as they can be. Playtech ranks as one of the top 10 best developers in the world, but it still doesn’t reach the same level that Microgaming and NetEnt have managed to achieve.

Red Tiger Gaming

Founded in 2014, Red Tiger Gaming quickly became one of the industry’s leading casino game developers thanks to the quality of the games that they started producing. The studio isn’t nearly as big as the two major studios in the world, but they still manage to constantly deliver world-class games that are now sitting among the “Most Played” sections in the world’s best online casinos. Many of Red Tiger’s best online slots are sitting atop of the slot categories in dozens of online casinos. You have to check them out and judge their quality yourself!


Novomatic games offer large payouts with less intricate graphic systems than those you find at the games created by the other developers that we’ve listed in this article. Novomatic is also one of the pioneers of live slot gambling, an innovative way to play online slots that is sure to change the way we see online casinos in the near future. With dozens of things to do and a plethora of rewards to enjoy at each Novomatic game, the company is sure to provide players with a unique experience in all of its titles.

Where Can You Play the Best Slots?

You can play all of these fantastic games and many more at any of our top-rated online casinos. We have a selection of the world’s best online casinos here, at The Casino Wizard, where you’ll be able to encounter some of the finest games that the industry has to offer. All of the top providers that we’ve mentioned in this article, as well as all of the games that are here, can be found at many of these world-class online casinos. As if that wasn’t enough, we also have a large selection of casino bonuses for you to choose from. The best casino bonuses can be found here, and many of them provide you with free spin bonuses or free money rewards that will allow you to play these games completely for free. If you’ve made it this far, we can tell that you’re eager to get down to business and play at the best online casinos in the world. Check out the bonuses, play the best games, and claim the best rewards on the internet!

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Last updated  February 2, 2024
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About the author



Chief Content Writer


Chief Content Writer

Marco is an experienced casino writer with more than half a decade of gambling-related work on his back. He took a keen interest in gambling as a young adult and started writing expert content for the casino and sports betting niche in 2015. Now, he specializes in online slots, table games, and sports betting – producing well-researched content on all fronts of the iGaming world.

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