Io Slot: Overview
The cosmically named Io is the second slot from developer ELK Studios to use their Gravity mechanic. The first, Cygnus, was another mysterious slot based in Egypt, but with an eye towards the stars. Io takes it one step further by locating the action up there amongst the celestial bodies. As well as the Gravity mechanic causing symbols to tumble randomly left or right, players get a host of features to accompany them on their trip off-world.
The voyage takes us to Jupiter where Io is one of its moons. This is no diplomatic mission to the stars though. It's actually a lot more amusing, described by ELK as a casino space station embarking on a journey to the frontiers of the solar system. Kind of like Captain Kirk on the Starship Enterprise, except the task here is to collect valuable minerals from the moon. It's all a bit of a laugh really, setting a jovial mode on the proceedings.
On each spin, 24 symbols fall into a grid made up of 6 columns, 4 rows, and 4,096 ways to win. Winning combinations form when three or more matching symbols land consecutively from the first column onwards. They can appear on any row and yet be a winner, hence the large number of win ways. Before getting started, players choose regular bets of 20 p/c to £/€100 per spin, or plump for one of ELK's four betting strategies.
Whenever a winner hits, the symbols involved in the combo vanish off the screen thanks to the Avalanche mechanic. When this occurs, symbols gravitate into the gaps, potentially creating more winning combos. Unlike most slots, the columns do not sit flush, so when symbols slink downwards, they can fall either left or right depending on gravity.
Avalanches also add an extra row, maxing out at 8 in height. Should you reach this level, then an uncountable 262,144 win ways come into play. Avalanches also mean long chains of wins can occur as gaps are plugged by the appropriate symbols to keep the procedure going. Once no new winners appear, then the next new spin begins.
As to symbols, the paytable has 8 regulars, divided into high and low pays. All are round disks, displaying classic slot icons such as J-A royals, stars, clovers, diamonds, and lucky sevens. Lucky sevens are worth the most at 5 times the stake for six of a kind, dropping to 0.20x for six Js. Helping cobble together combos, Io offers three wilds; one is a standard, the other are the Charged and Forge Wild covered below. Despite each one playing different roles, all wilds can substitute for any of the regular pay symbols.
A minor case of déjà vu flashed up when investigating the math model since it is almost identical to the one used before. That's not necessarily a bad thing though, because it produces some solid numbers to back up the gameplay. Roll on volatility which has been rated at 8/10, putting it in the medium to high range. Hit frequency is slightly higher than before on 24.6%, though RTP takes a tiny nudge downwards to 96%. Overall, players who like a bit more variance in their gaming will be satisfied, as they will be by the equally solid potential.
Io Slot: Features
As mentioned, there are 2 special wilds working alongside the standard wild. First is the Charged Wild which starts with 4 lives. It remains on the game area throughout a full reaction sequence and each time a Charged Wild is used as part of a win, it loses a life. When all 4 lives are gone, it vanishes off the grid.
Next, is the Wild Forge symbol eagle-eyed players may recognise in an altered form from Tahiti Gold or Voodoo Gold. In Io, when a Wild Forge appears, it fills an empty space below it with a multiplier wild. The value of the multiplier increases each time the Wild Forge is used with no set limit on how high it can go. If the Wild Forge falls to the bottom of the grid, it becomes a wild multiplier.
Getting to the big bucks, or precious minerals as they are known around here, requires harnessing the features. To help you on your way, ELK has included the Laser feature. When the laser symbols land, they shoot a beam of light, destroying itself as well as any regular symbols in its path, letting new ones slip into the empty spaces. If the beams from two laser symbols intersect, the symbols along the beams up to the intersection point become wilds.
Keep an eye out for the bonus symbols - 3 or more in view trigger the free drops bonus game. At least 7 free drops are awarded, up to 15 for 6 bonus symbols in view - keeping in mind free drops can be retriggered too. During the feature, the grid expands to its full 8x8 size, and any Charged Wilds or Wild Forge symbols remain sticky at the bottom of the grid between spins for the full duration.
Io Slot: Verdict
We might have traveled to the frontiers of space, but there isn't a huge amount players won't have seen before if they've played Cygnus. Aside from Jupiter out of the viewport, and some feature alterations, it's a whole lot like its predecessor. Even the math model is virtually the same as before, aside from a teensy drop of 0.1% in RTP. Potential has remained the same too on 5,000 times the stake, so no complaints there.
Graphically, Io is not as striking as Cygnus, nor as atmospheric, so if that's a concern, then the original wins out as the best one to go for. Otherwise, it comes down to feature preference. Io doesn't have the progressive multiplier quite like the first, but Forge Wilds go a long way to making up for it. Not to mention sticky wilds during free drops which can do some serious damage.
In a way, the Gravity mechanic series is looking like it might pan out like the Gold series. That means, retaining core stats and mechanics while making tweaks to features and scenery - and why not? It's a formula that has served Kane in the Gold series well, so there is no reason why it won't work in the Gravity range too.
The biggest difference really is the general approach to the theme. Whereas Cygnus was all about the mysticism, Io has a more light-hearted back story, and it is kind of fun pretending to be on a space casino revolving around an exotic moon, collecting precious minerals. Of course, a nice story is nothing in a slot without the gameplay or potential backing it up. Fortunately, Io comes up trumps in those regards, so while it's not exactly a brand new experience, it's a satisfying one all the same.
The second slot from ELK to feature their Gravity mechanic, Io shifts conventions of online gaming into science-fiction territory.