Once upon a time, slots had 3 reels and a single pay line. The gameplay was simple as can be, free of substitute symbols and special features to help you win.

A few decades later, we’re playing feature-rich “all ways pay” titles and winning over as many as 243 lines.

The progress continues thanks to innovative game studios such as Big Time Gaming and the unique Megaways concept which, rather than offer a fixed number of pay lines, makes the same game pay a different number of ways – up to 117,649!

These are some of the most volatile online slots ever made, so make sure you’ve got the bankroll to stomach some wild swings!

Below we’ve deconstructed some of our favorite online slots that have the Megaways functionality. You can also preview the bonus rounds of each by clicking on their respective logos.

Mystery Reels Megaways, created by Red Tiger Gaming, maybe using traditional symbols such as 7s, bells, and fruits but it’s nothing like classic one-armed bandits. A maximum of 7 symbols can land on each of the 6 reels, giving us up to 117,649 Megaways to win. Mystery Symbol creates clones in random reel positions and then reveals a single icon to award a payout.

Three Free Spins symbols trigger the bonus round, offering players to accept 8 free games or Gamble for more on the Free Spins Wheel. Those that choose the latter could win up to 20 free games on the first spin, 30 on the second and 40 on the third.

In the worst-case scenario, the house will pay only for 4. Each Free Spin win increases the multiplier which doesn’t reset. Mystery Reels Megaways has an RTP of 96.18% and a maximum win potential of 10,000x.

Dragon’s Luck Megaways is another Red Tiger title with the identical set-up – 6 reels, each able to display up to 7 symbols. Dragon Coins spin to reveal the same random icon, potentially waking up the two dragons on either side of the reel area while at it.

Once awake, dragons will breathe fire to flip Dragon Coins once more and transform symbols into those which pay more.

Players will additionally benefit from 2×2, 3×3 and 4×4 Super Symbols which split into multiple Dragon Coins and make the same magic happen again.

A win of more than $0.10 activates the Gamble button and offers players to access a configurable Gamble Wheel.  Plus and minus buttons increase and decrease the potential win while green/red sections of the Wheel display the chance of winning/losing.

Dragon’s Luck is, same as the other Red Tiger Megaways title, able to pay over 10,000x the bet. It offers a theoretical return of 92.71%

Bonanza is one of BTG’s own and also plays with 6 reels with up to 7 symbols each, meaning there’s up to 117,649 Megaways to win. The game area is designed like a mine with carts positioned on top of reels 2, 3, 4 and 5.

They’ll keep bringing a fresh set of symbols with each spin and thus contribute to their respective reels. Every win triggers a reaction which is, in essence, a creatively executed cascading reels feature.

Landing 4 Scatters that spell GOLD activates 12 Free Spins and every additional Scatter adds 5 more. Each reaction increases the win multiplier and there’s no limit to how high it can go.

While you’re playing on the house, Free Spins Scatters delivered by carts award 5 more spins (3 Scatters) or 10 additional ones (4 Scatters). BTG’s Bonanza slot has a 96% RTP and can pay up to 10,000x your stake.

Who Wants To Be A Millionaire, another Megaways slot from Big Time Gaming, also has up to 117,649 ways and replicates several popular features from Bonanza, including an unlimited Free Spins multiplier and reactions (Cascading Reels).

Instead of carts above reels 2-5, there’s a horizontal Extra Reel at the bottom filled with icons coming from the right.

It takes 3 Millionaire Scatters to win 8 Free Spins and launch the Hot Seat Free Spins Gamble with the potential to win up to 50 spins on the house. You’ll be selecting from answers A, B, C and D and move one level up with each correct guess.

A Lifeline is given with each gamble –50:50 removes 2 incorrect answers, Phone a Friend reveals the most likely answer, and Ask the Audience reveals all answer odds. Free Spins multiplier starts at 1 and increases after each reaction.

Free Spins Scatters appear only in the Extra Reel and award an additional 4 or 8 rounds (3/4 Scatters) free of charge. RTP is 96.27% and max win 50,000x your stake.

BTG’s Extra Chilli is a colorful video slot with up to 7 symbols per reel and up to 117,649 Megaways.

It also features reactions caused by winning outcomes and uses a horizontal Extra Reel which adds symbols to reels 2-5.

Landing 3 Scatters which spell HOT launches 8 Free Spins with an unlimited win multiplier and every extra Scatter awards 4 more.

Once again players are offered to spin the Free Spins Gamble Wheel and win up to 24 rounds on the house. Free Spins Scatters will only appear on the Extra Reel while you’re playing for free and add 4 or 8 spins to those already won.

If you wish to access the bonus round without having to wait for Scatters, you can pay the Feature Drop price or wait until Feature Drop symbols reduce it to zero. Once the price drops to zero, the feature is automatically triggered.

RTP varies; without buying the Feature Drop, it’s between 96.15% and 96.41%, and with the Feature Drop 96.26%-96.82%. Players can win up to 20,000x their stake.

BTG Megaways range also includes White Rabbit slot inspired by the famous novel Alice’s Adventures in Wonderland. Caterpillar can randomly add up to 4 Bonus Wilds which increase all combos by 2 or 3.

Scattered Rabbits appear on reels 2, 3 and 4, with a minimum of three needed to win 15 Free Spins. Every Cupcake symbol is replaced by 2 new icons and the number of symbols on the respective reel consequently increases by one.

Each reel can hold a maximum of 12 symbols; when it reaches the maximum number, the feature is retriggered and uses the Queen’s reel populated with extra Red Queens and Wilds.

White Rabbit also plays with Feature Drop and allows players to pay for Free Spins or wait until Feature Drop symbols decrease the price to zero. Every spin can normally produce 16,807 ways per spin but, thanks to the Extending Reels, you may get a whopping 248,832 ways to win.

The RTP is 97.77% when you purchase Feature Drop at full price and 97.24% when feature cost drops to zero. White Rabbit can pay up to 10,000x.

Blueprint Gaming has used BTG’s unique system to produce a Nordic adventure called Vikings Unleashed.

Each spin can have up to 117,649 ways to win, every win triggers a cascade and all Hammer symbols in view will reveal the same random regular game icon. It takes 4 Scatters to launch 12 Free Spins with an unlimited win multiplier.

Every extra Scatter adds 5 spins while Free Spins Scatters, willing to appear only on the top Extra Reel, add 5 or 10 free games. Prior to entering the bonus round, players are offered to Gamble the number of spins (max 27 to be won) and/or the starting multiplier (up to x10).

If you press the Free Spins Unleashed button, you’ll see big bet options of 25x, 50x, 75x and 100x bet which can buy 5, 8, 10 and 12 spins respectively. Having made your choice, you’ll be taken straight into the Gamble screen.

The game’s RTP ranges between 96.91% and 96.75% and the maximum win is 50,000x the bet.

Megaways applied to NextGen’s mega-hit allow players to win up to 117,649 ways. Winning combinations trigger reactions and Medusa’s Gaze feature, activated by Wilds in the horizontal Extra Reel, adds one or more substitute icons to the eel below the triggering Wild. Full Medusa review here.

Free Spins bonus round can be launched either by landing 3+ Scatters or via Buy Pass feature which triggers the bonus at a cost of 100x your bet.

You’ll get 10 spins to start with and 5 more for each new Scatter. Snakes appearing to the left and right of Extra Reel will attack each Soldier that shows up in this horizontal reel and transform it into Wild or Scatter. Free Spins win multiplier begins at x2 and increases before each reaction.

Once free games play out, players can choose to collect the win or replay the feature. If they pick the latter, the amount won is forfeited unless the feature was bought.

Medusa Megaways has a theoretical return of 96.286% without Buy Pass feature and 97.63% if Buy Pass is activated. Players can win up to 50,000x their bet.

Blueprint Gaming is another popular developer that chose to use BTG’s Megaways and make its Buffalo Rising slot pay 117,649 ways. The game incorporates Cascading Reels, Mystery Symbol which will transform into any other icon except for Scatter and Free Spins with an unlimited win multiplier.

The simultaneous appearance of 4 Scatters launches free games during which each reaction increases the multiplier by 1.

Players can pick among 3 Free Spins volatility options – 15 spins with the multiplier beginning at x1, 10 spins with the starting multiplier of x5 and 5 spins with the initial multiplier of x10, or go for Mystery Choice which can award any spins-multiplier combo.

Buffalo Bonus Bet allows them to buy the bonus at the displayed price and immediately start spinning for free. The main game has an RTP of 96.50% and Buffalo Bet 97.01%. The maximum amount Buffalo Rising can pay is 10,000x the bet.

Blueprint Gaming uses the same system in popular Genie Jackpots to enable a maximum of 15,625 Megaways.

Jackpot Genie can pop out from the magic lamp during any spin and grant you a wish – Wilds added to the reels on maximum Megaways, Wild Reel multiplied to a maximum of x5, Mystery Symbols or Wilds created to guarantee a win, or additional Bonus symbols on maximum Megaways for an increased chance of triggering the Bonus.

Multiple Bonus symbols award 10-20 Genie Freespins as well as the Cave of Wonders which allows the player to pick one of four lamps and reveal Mystery Wishes (Mystery symbols added to the reels), Unlimited Multiplier (increasing by 1 with every spin), Genie Streak (reels re-spin to better every win) or Locking Wild.

Players can buy the Bonus for 100x their stake and automatically trigger the Cave of Wonders. The theoretical return of the main game is 96.52% and Bonus Wish Bet 97.13%. The maximum win is 10,000x the bet.

Raging Rhino Megaways is an SG video slot with up to 117,649 ways to win.

It features a horizontal Extra Reel positioned on top and filled from the right, and this is the only place you’ll see Wild symbols during the base game.

Winning symbols explode to free space for new ones which can potentially deliver another payout on the same bet. Scattered Bonus symbols depicted as Diamonds trigger Free Spins.

You’ll get 8 to start with but can win 8 more by landing 3 or more Scatters once again.

Wild symbols may now appear on reels 2, 3, 4 or 5 as well as the top row. Free Spins multiplier increases by 1 with each cascade and there’s no limit as to how high it can go.

If you win less than 10x your total bet while spinning for free, a Bonus Guarantee of 10x total bet is awarded instead.

The expected return for this game is 96.18% and the maximum payout 10,000x your stake.

Relax Gaming applies the Megaways system to Temple Tumble slot and invites players to clear stone blocks in order to increase ways up to a maximum of 46,656.

There will be 3-24 blocks on the reel area at the beginning of every spin and those surrounding the winning symbols will be destroyed and disappear along with icons responsible for the payout.

This cascading action continues until there are no new wins.

Having destroyed all stone blocks, you’ll win 6 Free Spins playing with special blocks. There’s a choice of 3 Free Spin modes – Multipliers (blocks contain 1x, 2x or 3x added multipliers), Extra Spins (blocks contain 1, 2 or 3 additional spins) and Multipliers & Extra Spins (one or the other).

Destroyed special blocks will consequently either increase the multiplier or the number of Free Spins left.

Clearing all stone blocks in any of these modes wins you 3 more spins on the house. The game has an RTP of 96.25% and can pay up to 7,767x the bet.

Megaways can make one and the same slot pay a different number of ways thanks to the reel modifier mechanic which allows 2 – 7 symbols to land on a single reel on any given spin.

The system can consequently produce up to 117,649 ways to win and, as we’ve seen in BTG’s White Rabbit, even more than that. You won’t need a calculator to discover the number of ways available for each of your spins; the game itself does the math and displays this information above the reel area. However, it’s nice to understand the theory behind.

It’s quite simple, really. The number of ways is calculated by multiplying the number of symbols on each reel. For example, 7 symbols per reel on the usual 6-reel setup produce 7 x 7 x 7 x 7 x 7 x 7 = 117,649 ways. If these 6 reels on a certain spin hold 6, 5, 5, 4, 4 and 4 symbols respectively, you’ll have 6 x 5 x 5 x 4 x 4 x 4 = 9,600 ways to win.

Megaways concept was created by Big Time Gaming in 2016 and the first Megaways slots were only available at online casinos that have chosen to work with this particular developer.

Later on, BTG started licensing its unique system to other slot developers and by 2018 it has appeared in products from Red Tiger Gaming, Blueprint Gaming, SG, NextGen, Relax Gaming, Storm and Kalamba Games.

Players consequently benefit as Megaways thus become available in a bigger number of games and accessible to a wider audience.