Crystal Furnace

Crystal Furnace Slot Review

The reels sit inside a furnace firebox, a bed of smouldering coals running the full width beneath them and molten light leaking through the mortar of the brick arches on either side. Crystal Furnace is braver than it looks, because Eyecon have stripped the bonus round out entirely and let a single wild symbol do the work of a whole feature set: it’s a slot with one idea, and that idea has to hold your attention on its own.

Eyecon, the studio behind Fluffy Favourites and Enchanted Prince, has built it on a 5×3 grid that pays from both ends, running at 96.560% RTP. The best single line in the game is the BAR at five of a kind, worth 3,000x the total bet. The forge never quite goes out, and neither does the idea at the heart of it.

Base Game & Features

The game runs on a 5×3 grid with paylines that pay in both directions: every line counts from left to right and from right to left, and only the highest combination counts on each. Wins on different lines are added together, with each line win multiplied by the wager on that payline.

The both-ways rule is worth pausing on, because it quietly changes what a middle-reel symbol is worth. A BAR on reel 3 can complete a line running left from reel 1 or right from reel 5, so the same three middle reels are doing twice the connective work they would in a one-way game. It also means a paying line can be built from either end, which matters a great deal once the wilds start expanding.

The symbols are classic furnace-floor fare. A BAR and a lucky Seven sit at the top of the ladder, followed by five gems in yellow, green, blue, purple and red. A scatter symbol appears among the icons without a role of its own, which tells you where this game keeps its interest.

Every value below is a multiple of the total bet, not the line bet, for three, four and five of a kind respectively:

• BAR – 100x, 400x, 3,000x
• Seven – 50x, 200x, 1,000x
• Yellow Gem – 20x, 100x, 1,000x
• Green Gem – 20x, 40x, 100x
• Blue Gem – 10x, 30x, 100x
• Purple Gem – 10x, 30x, 100x
• Red Gem – 10x, 20x, 100x

It’s a tidy, old-fashioned ladder, and the values are quoted against the total bet rather than the line bet, which is worth checking before you compare them against another game’s paytable. A line bet multiple always looks bigger than the same prize expressed against total stake, and this game is honest about which one it’s using.

Notice the shape of the tiers. The Yellow Gem matches the Seven at 1,000x for five of a kind, which is unusually generous for the third symbol on the ladder, and blue and purple gems pay identically at every tier, so the middle of the ladder compresses while the BAR stands clear at the top. Four of a kind tells a similar story: the BAR jumps to 400x while the gems cluster between 20x and 100x.

At the bottom of the ladder the gems stay useful. Three of any gem still pays, from 10x to 20x depending on colour, so a cheap line of greens or blues isn’t a wasted result, and five of any gem is worth 100x or better across the board.

The wild substitutes for every symbol and appears only on reels 2, 3 and 4, which is exactly where the game’s one feature begins. Because wins count from both directions, a five-of-a-kind only needs the right three middle reels to connect with matching symbols on reels 1 and 5 from either side.

Crystal Furnace Bonus Features

The Expanding Wild Re-Spin feature is the whole bonus side of Crystal Furnace, and it runs on a short, strict set of rules:

• One or more wilds anywhere on reels 2, 3 or 4 start the feature
• Each wild expands to cover all three positions on its reel
• Payouts are calculated after the expansion, not before
• Wild reels are held while the remaining reels re-spin
• Re-spins continue while fresh wilds land on unheld reels
• The feature ends when no new wilds appear, or when reels 2, 3 and 4 are all held
• Maximum of three re-spins per feature

Walk it through from a single wild. It lands on reel 3, expands to fill that reel top to bottom, and any lines it completes are paid at full expanded value straight away. Reels 1, 2, 4 and 5 then spin again while reel 3 stays frozen. If that re-spin throws a wild onto reel 2, that reel expands too, is paid, and locks alongside the first.

One more re-spin follows, and it’s the one that matters. With reels 2 and 3 both held as stacked wilds, any matching symbols landing on reels 1, 4 and 5 connect from both ends at once, and several lines can pay together on the same re-spin. If the third wild arrives on reel 4, the feature is over by rule: all three middle reels are held, and there’s nothing left to re-spin.

The practical ceiling is that full build: three held wild reels in the middle, with every paying symbol on reels 1 and 5 connecting from both ends. Payouts land after each expansion, so every step of the build is paid on its own merits rather than only at the end.

The two-wild build is the more common stopping point, and it’s stronger than it sounds. Stacked wilds on reels 2 and 3 turn every BAR, Seven or gem on reels 4 and 5 into a potential five-of-a-kind connector, paid left to right, while anything matching on reel 1 can complete a shorter line from the other direction on the same spin.

There’s nothing else attached: no free spins round, no pick-me, no second modifier. The scatter carries no stated function, the wild is the only special symbol that does anything, and the three-re-spin cap keeps the whole feature inside a single spin’s worth of drama.

Our Honest Verdict

Overall Rating: 7.1/10

This is a slow-burn game, and the reason to pick it is the one moment the furnace opens: three wild reels locked in the middle and the outer reels spinning into a grid that pays from both ends. That build is moreish in a way Eyecon’s busier titles aren’t, because nothing competes with it.

The wild is also the strength. Both-ways paylines mean a single expanded wild on reel 2 or 4 is never a dead result, and the ladder pays fairly against the total bet rather than flattering it with line-bet multiples.

But one idea is all you get. Once the feature’s three re-spins are done there’s nothing to wait for except the next one, and the gems between BAR hits are filler you’ll stop noticing. It suits Eyecon loyalists and anyone who likes a focused, no-frills grid; anyone chasing layered bonus rounds will find the coals cool quickly. For the right player, that single, well-fed fire is plenty.

Crystal Furnace FAQs

• What is the RTP of Crystal Furnace?

  Crystal Furnace runs at 96.560% RTP, which sits comfortably above the typical industry average.
• Who makes Crystal Furnace?

  Crystal Furnace is made by Eyecon, the studio behind Fluffy Favourites, Enchanted Prince and Irish Luck.
• What grid does Crystal Furnace use?

  The game plays on a 5×3 grid with paylines that pay from left to right and from right to left.
• How do you trigger the Expanding Wild Re-Spin feature?

  Any wild appearing on reels 2, 3 or 4 starts it. Each wild expands to cover its entire reel, and the wild reels are then held while the rest re-spin.
• How many re-spins can the Expanding Wild feature award?

  Up to three. Fresh wilds on unheld reels keep it going, and it stops once no new wilds land or the middle three reels are all held.
• Which reels can the Wild symbol appear on?

  The wild only appears on reels 2, 3 and 4, and it substitutes for every other symbol in the game.
• Do paylines pay in both directions in Crystal Furnace?

  Yes. All line wins pay from left to right and from right to left, with only the highest combination counting on each selected payline, and wins on different paylines are added together.
• What is the biggest win in Crystal Furnace?

  The BAR is the top-paying symbol, and a full line of them with the middle reels held wild can stack several high-value lines into a single payout, with wins counting from both ends of the grid at once.