IO Slot Review

The IO slot is from ELK Studios and begins with 6 reels and 4,096 ways to win. With a space theme, you head to Jupiter from just 20p a spin on all devices. It uses gravity mechanics where symbols are drawn to the left and right on their way downwards after a win. Each win also adds a row which gives you more ways to win, up to 262,144 ways to win.

With an Avalanche feature, IO comes with a Charged Wild which has 4 extra lives which are lost when it’s part of a win. The Wild Forge adds a multiplier wild which increases and the Laser sees symbols turn into wilds. Then there’s a Bonus Game feature where you get free spins where charged wilds and wild forge symbols are collected at the bottom between free spins. It has an RTP of 96% and a max win of 5,000 x stake per spin. Find out more in our IO slot review. Want to play right now? Check out the best IO casinos.

Where to Play IO Slot

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IO Slot RTP, Details & Wager Limits

The IO slot begins with 6 reels, 4 rows and 4,096 ways to win. A winning combination is formed when 3, 4, 5 or 6 matching symbols appear from left to right on adjacent reels starting from the first reel. Being an Avalanche game, each win adds more rows and paylines with up to 8 rows and 262,144 ways to win.

The minimum stake per spin is 20p whilst the most you can play is £100 a spin. There is an Auto button which allows you to use the Auto Spin function. You can simple choose up to 100 auto spins. If you click on the 3 lines icon and go to settings, you can enable Quick Play to benefit from faster spin speed.

When it comes to volatility, IO is a medium to high variance slot and rated 8/10 by ELK Studios. The hit frequency is 24.6% meaning nearly a quarter of spins will result in a winning outcome. Like other slots from this provider, this max win is 5,000 x your total stake per spin. This can be achieved on a base game or free spin.

Bonus Features in IO

IO comes with 5 bonus features in total. Key to the gameplay is the Avalanche engine which has features in other ELK Studios titles like Cygnus. There are also Charged Wilds, Wild Forges, Lasers and free spins/drops. Let’s dig a little deeper.

Avalanche feature

Every winning combination sees the Avalanche feature come into play. Winning symbols explode to make way for new symbols coming in. Then a new row is added which gives you more ways to win. The process repeats itself if you get another winning combination.

The number of rows can increase up to 8 which will in turn allow up to 262,144 ways to win in total. Here’s the breakdown of the number of ways to win for each extra row:

    • 4 rows = 4,096 ways to win
    • 5 rows = 15,625 ways to win
  • 6 rows = 46,656 ways to win
  • 7 rows = 117,649 ways to win
  • 8 rows = 262,144 ways to win

Charged Wild feature

IO comes with a Charged Wild symbol. This symbol has 4 extra lives as such. When part of a winning combination, it loses a life. When all 4 lives are lost, it disappears from the reel set. The Charged Wild substitutes for all regular symbols.

Wild Forge feature

There is also a Wild Forge symbol. This fills an empty space below with a multiplier wild. Every time the Wild Forge is used, the value of the multiplier increases. The Wild Forge then transforms into a multiplier wild once it has reached the bottom of the reel set.

Laser feature

Look out for laser symbols appearing on the reels. When the beams from 2 lasers intersect, the Laser feature is triggered. The Laser and regular symbols along the beams turn into wilds. A single Laser will remove itself and all symbols along its beam.

Bonus Game feature

The main attraction of the IO slot is the Bonus Game feature. This is played when you land 3 bonus scatter symbols. You will then get 7 free spins with 8 rows and 262,144 ways to win. You can also retrigger the feature (with 3 or more scatters) to give you another 7 free spins and 14 in total.

Charged Wilds and Wild Forge symbols are collected at the bottom of the reel set between free spins to increase your winning potential. This allows for multiplier wilds on every free spin.

Theme – Audio & Design Features – head to outer space

IO slot base game

The IO slot has a space theme as it focused on a casino space station which embarks on a journey around the solar system. With the solar system in the backdrop, the graphics and quite simple and dominated by the colour purple. It’s not the best looking slot game we’ve come across. There’s no soundtrack as such which gives the impression of space quite nicely actually.

Symbols appear on round circles and include low value A, K, Q and Js. You’ll also see stars, 4-leaf clovers, diamonds and lucky red 7s. The lucky red 7 symbol is the most lucrative giving you 1, 2, 3 or 5 times your stake for 3, 4, 5 or 6 in combination. There is also wild symbol (W) which substitutes for all symbols mentioned.

Despite being quite simple graphically, the IO slot can be played on desktop, mobile and tablet devices. It looks particularly good on smartphones as ELK Studios are a mobile-first provider. The reel layout fills a mobile screen quite nicely.

IO Review Summary – simple yet appealing

The IO slot is simple in the way it looks. It’s all about the Avalanche feature which adds more rows and ways to win into play. The Wild Forge and Laser feature are nice additions which can add plenty of wilds and multiplier wilds to the reels.

The bigger wins will come in the free spins as you’ll play with the maximum ways to win from the off. Let’s just hope the Wild Forge symbols offer a big multiplier. As with other ELK Studios games, the max win is capped at 5,000 x stake. It would be ideal if they raised that number higher.

That aside, IO is a simple and entertaining slot game which will appeal to players who like cascading reels slots with big win potential. If it’s the theme you like, the Starburst slot by NetEnt is simple yet just as appealing.


What is the IO slot RTP?

The IO slot RTP is 96% which is normal for an online slot. It has a hit frequency of 24.6% and is a medium to high variance game. Most wins will be smaller with the larger wins coming from the Wild Forge multiplier wilds and the free spins.

? What is the IO slot max win?

The max win per spin from the IO slot is 5,000 x your total stake. The key to winning big is by increasing the number of ways to win to 262,144 and benefiting from multiplier wilds. Your chances increase in the Bonus Game feature as you play with 8 rows and Wild Forge symbols are collected at the bottom between free spins.

? Where can I play the IO slot?

ELK Studios slots are available at many online casinos. All regulated by the UK Gambling Commission and reputable, check out the three best IO casinos which have welcome offers for new players.

How does the Avalanche feature work?

Every winning combination sees another row added to the reels. With every new row, the number of ways to win increases. Consecutive avalanches/wins can lead to 8 rows which will allow 262,144 ways to win in total. In the Bonus Game feature, all free spins are played with the maximum number of rows and ways to win.

IO Slot Information

  • Game:
  • Provider:
    ELK Studios
  • Type:
    Video Slot
  • Reels:
  • Paylines:
  • Stakes Range:
    0.20 to 100.00
  • Max Win:
    5,000 x
  • Bonus Features:
    Yes (5)
  • Free Spins/Multiplier:
  • RTP %:
Review by Chris Taylor

Review by Chris Taylor

Chris is a slots expert that has reviewed and played over 4,000 online slots. Having being in the iGaming industry for over 16 years, he knows how slots work, how bonus features are triggered and how the RTP and variance affect the gameplay.

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