Released: 13 Oct 2013

Big Thunder is a game by Ainsworth who decided to go deep into the jungle for inspiration for the game's symbols and theme. The result is a mighty slot of 5 reels and 30 paylines that is able to deliver 4 jackpot prizes, besides the base game wins. And did I mention there is a Big Thunder free spins bonus too? Check my full Big Thunder Slot Review for more details on this exciting release!

Big Thunder  Slot

Big Thunder Slot Review

Last Updated at 26/09/2022

Table of Contents

  1. About Big Thunder Slot
  2. Design, Symbols and Graphics
  3. RTP, Variance and Payouts
  4. Gameplay and Features
  5. Our Verdict

Play the Big Thunder slots for a chance to win the top jackpot or one of the other jackpot prizes and base-game wins! On top of that, there is a Free Spins bonus where multipliers can reach 5x. Without further ado, here is my full Big Thunder Slot Review where you’ll discover how to win up to 10,000x the stake!

big thunder slots

About Big Thunder Slot

When the time has come to walk on the wild side of things and explore the deep African rainforests, see what's underneath the canopy on the Big Thunder slot! This five-reel game takes the players to some exceptional reel action that comes with the potential for mini, minor, maxi and major winnings. 

Developed by Ainsworth, the Big Thunder slot has 30 paylines to form winning combinations on. To win, you have to land 3 or more matching symbols across a payline, from left to right. But, before that, make sure to set your preferred bet and then start spinning. The Big Thunder slots accept betting options that range from £0.01 to £3000 per spin.

As I said above, Big Thunder slots has 4 jackpots that the luckiest players could win. In addition, there is the well-known Free Spins feature where you can win up to 10,000x the stake. Impressive, right? Check below to see how to benefit from these extras!

Design, Symbols and Graphics

As soon as I opened the game, I noticed that Ainsworth took inspiration from Peter Jackson's King Kong to develop the Big Thunder slot. Here, everything revolves around the mighty gorilla that is the king of the jungle. The reels are placed deep in the jungle, while the soundtrack is engaging.

big thunder slot ainsworth

The reels are filled with a variety of symbols. To start with the low-paying ones, they are designed as Royals (9, 10, J, Q, K and A) in different colours. On the other hand, the high-paying symbols are jungle-themed and include a king strike, a drum, a waterfall, a mask, a shield, and a snake.

In addition, Big Thunder slots comes with a wild and a scatter symbol. The wild is the mighty gorila himself, while the scatter is the game’s logo. The wild substitutes for the regular symbols to help you form wins. And as you might’ve guessed, the scatter triggers the Free Spins round.

RTP, Variance and Payouts for Big Thunder Slot

The theoretical RTP of the Big Thunder slot is 94.38%, which was a bit disappointing for me as the industry standard is 96%. Plus, the variance is high, so you should expect to land less frequent but more valuable wins. Apart from the jackpots, the maximum win is capped at 10,000x the stake.

If you want to learn more about these technical terms and how they work in online slots, check our detailed Variance, Volatility and RTP Guide.

big thunder slot

Gameplay and Features on Big Thunder Slot

Now comes the most exciting part of any slot game, including Big Thunder slots - the bonus features! I was lucky enough to trigger the Free Spins and experience it first-hand, so here are my thoughts.

Free Spins Feature

To trigger the Free Spins feature, you need to land 3 or more scatters on the same spin. This will give you 15 free spins to play with.

During the Free Spins, a bonus reel will appear with 2 new bonus symbols (x3 and x5), as well as the game logo. When the x3 symbol appears on the reels, all wins will be tripled. And when the x5 symbol appears on the reels, all wins will be multiplied by 5. 

Finally, when 3 or more game logo symbols appear on the reels, you’ll win an additional 5 Free Spins.

big thunder slot free spins

King Strike Bonus

During your gameplay, you’ll notice the small 6th reel on the right side of the screen. That is the King Strike reel that triggers the King Strike bonus.

The King Strike bonus is awarded when 5 of a king ‘Waterfall’, ‘Drum’, ‘Shield’, ‘Snake’ or ‘Mask’ win occurs, along with the ‘King Strike’ symbol on reel 6. There are 4 jackpots that you can win: Major, Maxi, Minor and Mini.

The current value of each jackpot is displayed above the reels, and you can see it at any point during your gameplay.

Other Ainsworth Slots

As part of its mission to provide high-quality innovative gaming solutions globally, Ainsworth is a provider whose games can be worth trying. So if you’re looking for other Ainsworth slots to try your luck at, I recommend the following titles: Money from Mars, Long and Happy Life, and Royal Swan.

big thunder slot review

SlotsWise Verdict

Big Thunder is a decent slot, with great features, big wins, and progressive jackpots. I was quite disappointed by its RTP rate, but that’s due to the jackpots’ contribution. So, if you don’t mind that, I invite you to check Big Thunder slots! Even if you cannot win the jackpot, you can still win up to 10,000x the stake, which could turn into an awesome prize.

Discover the Big Thunder slot by claiming a welcome offer from this page and play at top-rated online casinos.

Key Features
  • ProviderAinsworth
  • Reels5
  • Min Bet0.01
  • Max Payout10000.00x
  • RTP94.38
  • Paylines30
  • Max Bet3000.00
  • Bonus Rounds2
  • VarianceHigh
About The Author

Simona Boshkova


I am a slots expert with years of experience in the iGaming industry and have reviewed thousands of online slots! My favourite game is Superstars because I love how NetEnt included all legendary slot characters in the gameplay.

Similar Games
Want great offers sent straight to your inbox?

Enter your email below and we’ll do all the hard work for you

Welcome to our Mailing List

Keep a look out for our emails containing great offers!