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io Slot

Io
Io
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Updated: 22.07.2025
Reviewed by: Fabio Duarte

Welcome to Io! This is a space-themed slot machine, released on 02/06/2020 from ELK Studios with a similar format to Cygnus. Its avalanches give you up to 262,144 ways to win and you have 3 base game features plus free spins round to help you land massive prizes.

Using this review you will be able to learn about the main details of this title including its mathematical model, design, bonus features, bets, and mobile compatibility. We'll also reveal all of its hits and misses so you can decide if it's worth your attention!

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In this review
  1. Slot details
  2. Theme
  3. Bonus Rounds & Free Spins
  4. Summary
  5. Where to play
General information about Io slot

General information about Io slot

Rating by Fabio Duarte:
7.9
User’s Rating: Not rated yet
ELK Studios
Write a review +25 SJ points
  • Release Date:
    02.06.2020
  • Volatility:
    High
  • RTP:
    96.0%
  • Multiplier:
    Yes
  • Max. win:
    5,000x
  • Bonus game:
    Yes
  • Free spins:
    Yes
  • Scatter Symbol:
    Yes
  • Wild symbol:
    Yes
  • Symbol Stacked:
    No
  • Jackpot Game:
    No
  • Slot lines:
    4,096
  • Slot reels:
    6
  • Layout:
    6-8
  • Stakes range (€/£/$):
    0.20 to 100
  • Slot Theme:
    Futuristic
  • Technology:
    HTML5
More infoLess info

Licensed and tested by

  • Gambling Comission
  • MGA
  • ONJN

How to Play

The slot starts with 6 reels and 4,096 ways to win. Each time a win is created, the number of ways to win increases. It uses a unique "Gravity" mechanic and after a win, all symbols move to the left side of the screen. You can bet from €0.20 to €100 per spin.

To start this space journey all you need is:

  • Open Io at your chosen casino
  • Find out the value of symbols
  • Carefully read the rules of bonus features
  • Choose a bet: from €0.20 to €100 per spin
  • Set the reels in motion!

Io RTP and Volatility

7.8 
This slot features high volatility and 96% RTP.
This slot machine comes with high volatility, which means that you will have to work hard to create a prize combination of premium symbols or activate a bonus feature. The advantage of this volatility is that you can get really big payouts! The theoretical return is 96% which is the industry average and this is a good thing as many slots come with RTP well below the industry average.

Theme

7.9 

This is a futuristic space-themed slot machine set against a dazzling backdrop of stars and Jupiter. There's even a bit of storytelling here! We're supposed to be aboard a casino space station that's heading for Earth, but it's denied entry. Instead, it heads for Jupiter and is pulled by gravity towards the planet's 4th largest moon, Io. The backstory is quite interesting and we love the look of this slot. Both of these aspects work together to create a fun experience!

Let's see what the paytable offers. Premium symbols are Lucky 7, pink diamond, 4-leaf clover, and blue Star. All the playing card suits you can see here are low-paying symbols. There is also the letter “W” which acts as a special Wild symbol. It substitutes for all regular symbols and the Wild only combo pays as a combo of higher-level premium symbols.

Theme
Io slot paytable

Mobile Compatibility

Mobile Compatibility
What could be better than being able to play wherever you are? Fortunately, ELK Studios is a provider that does everything for the convenience of its players, so all of their slot machines, including this one, are created using HTML5 technology. You can spin the reels of Io on any modern smartphone or tablet as it is perfectly compatible with mobile devices. The slot does not require any apps to be installed, so you can simply log into the casino site from your mobile device and launch it using your web browser.

About ELK Studios

This slot was created by ELK Studios, a young Swedish gambling provider that specializes in top-notch slots. The company has an amazing portfolio of unique products and operates on a “mobile-first” basis, that is, they use a development method that prioritizes the mobile version. Their products support 20 different languages as well as multiple currencies. Among their popular games are Zulu Gold, Book of Toro, and Fate of Fortune.

Bonus Rounds & Free Spins

8 

Wild Lives

There are a number of bonus features in this slot machine and the first one you will likely encounter in the base game is the Charged Wild. This Wild symbol has 4 lives and 1 life is used when it is included in the prize combination. Then it does not disappear but remains on the playing field with its remaining 3 lives. This will continue until the next spin or until all 4 lives are used up.

Wild Forge

There is also a Wild Forge feature. It fills the space below the Wild symbol and applies a multiplier to it. Each time a Wild symbol is included in the prize combination, the multiplier increases.

Laser

When 2 laser beams intersect, all symbols between them and the two symbols from which the lasers come out become Wild. If there is only 1 laser on the playing field, it will remove all symbols in its path.
Io slot laser symbol

Free Spins

Landing 3 Bonus symbols will instantly trigger the free spins feature with 7 free spins! During this bonus feature, you always play with the maximum number of ways to win (262,144). Charged Wilds and Wild Forges gather at the bottom of the playing field to help you land some really massive payouts.

Io Demo Play

The provider has created a Demo mode for this slot machine, which allows you to spin its reels making bets with "fun" coins, not real money. This mode is easily accessible to every player and you don't even need to create a casino account to use it. Play for free for as long as you want! If you have used all the provided amount of "fun" coins, just reload the page with the slot machine and continue to test the game for free.

Max Win

8 
Win up to 5,000x the bet.
The maximum payout in this slot machine is 5,000x the bet. This is a good max win potential for a high volatility game and you will be able to unleash it during the Free Spins feature that comes with the maximum number of ways to win, Charged Wilds and Wild Forges. Good luck!

Io Video Review

Denied immediate access to Earth, the casino space station embarks on a journey to new promising frontiers in the solar system. Drawn by the superior gravity of Jupiter, the course is set to the fourth-largest moon, Io! A geological, volcanic marvel, and home to immense amounts of invaluable minerals. Io is a universal slot with gravity mechanics that draws symbols left and right on their way downwards, bringing more of them into play. Rows are added for each win, up to 8 rows and 262 144 ways to win. For more information about the game, please visit: https://www.elk-studios.com/games/io/

Overall Rating

7.9
Did you like Cygnus? Then you'll probably love Io too! There is little difference between these 2 slot machines, although it would be wrong to call it a clone. Of course, the theme is completely new, as is the backstory, but the gameplay bonuses and the math model are somewhat similar. That said, Io has enough tweaks and twists to make itself a unique experience while still satisfying fans of the previous game. This release is worth your attention and we expect that this will not be the last thing we see in the gravity series from ELK Studios!
Hits
The gravity mechanics are still interesting
Wild Forge Multiplier
Laser symbol Transformation
Free Spins with the max number of ways to win
Misses
RTP is 0.1% lower than the first slot from the gravity series
High volatility

FAQ

Why should I try this slot?

You should try this slot as it is the second release in the popular gravity series with gravity mechanics, Wild Forge Multiplier, Laser symbol Transformation, and Free Spins with the 262,144 ways to win!

Can I spin the Io reels for free?

Yes, the provider has created a Demo mode for this slot machine, which allows you to spin its reels making bets with "fun" coins. Play for free for as long as you want!

What is the Return to Player (RTP) in Io?

The theoretical return is 96% which is the industry average and this is a good thing as many slots come with RTP well below the industry average.

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Fabio Duarte
Fabio Duarte
Expert in: News, Blog, Slot reviews, Payments
Fabio is a young writer with +6 years of experience in gambling & betting. Fabio creates professional reviews of casino and slots. Every single article Fabio made exhibits deep analytical skill and comprehensive coverage of a topic. It’s Fabio – one of the leading authors on slotsjudge.com.

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