There are good, terrible, awesome, and strange slots in online casinos.
Then, there are slots that define their own genre. These slots impacted the whole industry and changed forever how game studios make games.
Here, we will have a closer look at these (often) iconic games that started trends and led slot developers to copy, be influenced by, and innovate even further.
Book of Ra (“Book of” Slots)
If you visit any online casino, you will often find Book of Dead in one of the most prominent places in the game lobby.
However, although BOD is the most famous and popular “Book of” slot online, another one started it all, and that Book of Dead is.. let’s say.. influenced by: Book of Ra.
Book of Ra is one of the most played land-based casino slots ever created and a game you often find in these casinos today. The online version hasn’t gained as much success but can be found in some selected casinos like LeoVegas.
Nowadays, you can find endless “Book of” slots online where the selected symbol can expand and cover full reels in the bonus games, but Book of Ra is the one that started it all.
Reactoonz (Cluster Pays)
Reactoonz is a slot from Play’n Go that was released in 2017, and 6 years later, it can still be found in online casinos’ most popular lists. For example, in Finland, it is one of the best-performing slots in 2023, although so many new slots fight for players’ attention.
Reactoonz can be seen as quite a strange or odd slot from an outsider’s point of view.
You have these funny-looking aliens cramped up in a 7×7 grid where 5 or more of them must land connected in a cluster to create a win. The winning symbols are removed and replaced by new ones until the wins stop. On top of these, you have different modifiers that can help you achieve wins.
This Cluster Pays mechanic started its own genre that many other game studios have tried to copy. Play’n Go has also released several sequels to the original game, but none of them have achieved the success of the first Reactoonz slot.
Money Train (Hold and Win with modifiers)
Game developers often release sequels and follow-ups or even clones of popular slots, but few have become as popular as the Money Train series.
The first Money Train is the one that set off the trend by releasing slots with a Hold and Win mechanic (incl. modifiers).
You have surely come across several slots where the bonus game starts with three spins that reset when a new symbol lands on the reels.
You might land multipliers, modifiers, and other extras, and all this came from the clever people at Relax Gaming, who invented and released the first Money Train slot.
Few game mechanics have been so influential as the Megaways engine, where each spin is played with different ways to win, where the maximum is usually capped at 177,649 ways.
The slot that started the hype was Bonanza Megaways from 2016, where you aim at landing the letters G-O-L-D to enter the Free Spins rounds.
It is all accompanied by a soundtrack played by Nik Robinson, CEO and founder of Big Time Gaming. The instrument he used? – A Banjo!
This odd and wonderfully different soundtrack also made it into our slots with the best soundtrack top list.
If you enjoy the Bonanza slot, try the sequel Bonanza Falls as well, which offers an increased max win potential and has a few new features up its sleeve.
Mega Moolah (Progressive Jackpot slots)
Jackpot slots will always be popular as you can win millions, even though you are betting with pennies or cents.
There are several popular jackpot slots, including the oldies Mega Fortune, Mega Fortune Dreams, and Hall of Gods. Still, the main progressive jackpot slot that most slot players are familiar with is Mega Moolah from Microgaming.
Mega Moolah has handed out several million jackpots and has been the world record holder several times for the biggest-ever casino wins won online.
Gonzo’s Quest (Avalanche)
Few slots are as iconic as Gonzo’s Quest from 2011, created by game studio NetEnt.
In this charming slot, you help the explorer Gonzo find the lost city of gold, El Dorado, and the richness waiting there.
Apart from enjoyable graphics, the Avalanche mechanic made this slot stand out. It is played with symbols falling into the reels instead of spinning reels, which was a common practice back then.
Since the release of Gonzo’s Quest, other game studios have tried to replicate the success of this slot by creating games using a similar Avalance game mechanic. Still, none of them have come close to the popularity of the original Gonzo’s Quest.
Several sequels to the game have been released, including Gonzo’s Quest Megaways and a VR version.
Fishin’ Frenzy (Fishing)
When visiting online casinos, it’s hard to miss the number of fishing slots available. Finding a game studio that hasn’t released some slot version using a fishing theme is challenging.
The most famous one is probably Big Bass Bonanza or one of its +10 sequels, but the one that started it all was Fishin’ Frenzy by Reel Time Gaming, released in 2014 by Blueprint Gaming.
So, if you want to go down memory lane and try the first fishing slot that started this whole fishing mania, give Fishin’ Frenzy a few spins.
Sweet Bonanza (Candy)
Candy-themed slots are also one of the top trends, but which slot started it all?
Sweet Bonanza might not have been the first candy-themed slot on the market. Still, it took the genre to the mainstream channel, as almost every game studio releases one or several slots using this theme and similar graphics.
Sweet Bonanza is a Scatter Pays slot where you need to land 8 or more matching symbols anywhere on the screen to create a win. In the Free Spins, you can hit wins of up to 21,100x by landing high-value multipliers combined with normal wins.
Dead or Alive (Wild West)
Dead or Alive from NetEnt is one of the oldest slots in this list and a proper classic.
It was released back in 2009, and at the time, it was considered a crazy, highly volatile slot as you could win up to 13,888x the bet.
However, that winning potential is nowhere near the highest max win slots on the market today.
Dead or Alive, with its sticky wilds in the bonus game, quickly became a fan favourite among players looking for riskier slots, and in 2019 the excellent sequel Dead or Alive 2 was released.
Nowadays, there are plenty of Wild West-themed slots on the market, but the one seen as the genre’s game changer is the original Dead or Alive.
Cleopatra (Egyptian mythology)
Another popular theme in slots is the Egyptian mythology. The already mentioned “Book of” slots have contributed to the popularity of this genre, but there are plenty of Ancient Egyptian themes out there with different mechanics.
However, the slot that defined this genre is the old-time classic Cleopatra.
Cleopatra is more familiar among brick-and-mortar casino players and can be hard to find online nowadays as it has aged and lost its popularity on internet versions, but it’s a legendary slot that needs to be mentioned.
Cleopatra was also one of the first slots with a free spins + multipliers bonus, which became the industry standard for a while.