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Thunderstruck Slot Review

Thunderstruck slot review

Thunderstruck Game Details

RTP: 96.10%
Reels: 5
Paylines: 9
Jackpot: 750 x Stake
Progressive: No
Bonus Round: No
Free Spins: Yes
Auto Play Feature: Yes
Scatter Symbol: Yes

Where To Play Thunderstruck

Karamba Casino
3.8 out of 5 stars
4.1 out of 5 stars

If you’ve ever frequented online casinos before there’s a very good chance you’ll have come across a game called Thunderstruck – or its sequel, Thunderstruck II. They’re both from one of the world’s largest game developers, Microgaming, and the games have proved immensely popular, offering players the chance to head back to Ancient Nordic culture.

In this Thunderstruck slot review I’m going to be taking a look at the original version of the game. It’s often overlooked, with players favouring the sequel – but don’t let that put you off. The original offers some fantastic win-potential, and it’s ideal for those wanting a classic, simple slotting experience.

Thunderstruck is built around a 5-reel, 3-row format and there’s a total of 9 paylines. Depending on whether a mobile slots site is offering the revamped HTML5 version of Thunderstruck or not, you may be able to adjust the number of paylines active – although from my experience it’s quite rare these days.

The game can be played from as little as 1p per spin (assuming you are able to change the number of lines played), and the maximum spin varies between £15-£30 depending on which casino you’re playing at.

How To Play

I think it’s fair to say that Microgaming’s older user-interface (the one that Thunderstruck largely still uses) isn’t anywhere near as slick as what you’ll find most game developers pushing out today. It looks a bit clunky (and that’s an understatement) and the old-school golden bar can be seen at the bottom of the screen; welcomed nostalgia for old-school players.

For this review, I’m going to assume you’re playing a version of the game where you are able to change the number of paylines active. If you wish to change the number of paylines, you simply need to click the “Select Lines” button. This will then cycle through the various lines available, letting you choose to play between 1 and all 9.

To the right-hand-side of this button you’ll also see a “Select Coins” button. This is how you’ll be choosing your stake size, and again, you can cycle through the various stakes on offer until you find one that suits your personal preferences.

Now, you’ll also see a button called “Expert”. Clicking this will bring up a few additional options, which I’ll explain now. Firstly, you’ll notice that the autoplay function becomes available to you. This allows you to pre-program up to 100 spins to play out automatically.

It’s ideal if you’re wanting to sit back and relax as the game plays, without worrying about having to spin each spin manually. You’ll also find that you’re able to activate the “quick spin” feature, which reduces the time it takes for the reels to spin; perfect for those wanting to skip as much of the base-game as possible and reach the bonus round.

You’ll also see a red button with the text “Help”. Clicking on this will open up the game’s paytable; here, you’ll be able to view information about the game’s symbols and their subsequent payouts.

You can also view more information, like the rules of the game – and it also gives you a breakdown of how the bonus feature works, along with what the RTP is for the version of the game you’re playing is.

Symbols and Payouts

You’ll find that playing card values, including 10, jack, queen, king, and ace are used for Thunderstruck’s lower-paying symbols. Interestingly, Microgaming have also decided to include a 9 – the lower-paying symbol.

Thunderstruck paytable

This is unusual, as this didn’t really start becoming popular until many years after Thunderstruck was released. The payouts for the lower-paying symbols are pretty poor, if I’m being honest with you. Don’t expect to walk away with any sizeable wins by matching 5-of-a-kind combos of these lower-paying symbols, unless you’re in the bonus round.

The more lucrative-paying symbols are all theme-specific, and include a Horn, a Staff, Thor’s Hammer, a Mighty Castle and Thor himself. Thor is the game’s wild symbol, and when he contributes towards part of a win he’ll apply a 2X multiplier to that win.

Unfortunately, these multipliers do not multiply against one another, so it doesn’t matter how many of them you land – they’ll always be worth 2X. You’ll also notice some Goat scatter symbols on the reels. These are paying scatter symbols, and they’re also key to triggering the main bonus round, which I’ll be covering in the section below.

Bonus Features

Thunderstruck has just one main bonus round – although there is a separate gamble feature which I’ll look at too. Let’s begin with a look at the main free-spins feature.

Free Spins Round

Landing 3, 4, or 5 of the scatter symbols anywhere in view will activate the main free-spins bonus, and this is, arguably, what you’re looking for when playing Thunderstruck. You’ll then receive a total of 15 free-spins.

Thunderstruck Slot free spins

It doesn’t matter how many scatter symbols you land in view, as, like with almost all of Microgaming’s video slots, additional scatter symbols don’t award additional spins. Instead, they award a higher cash prize. You will then receive a total of 15 free-spins, which are played on a slightly different reel set.

During the bonus, the Thor’s wild symbols are still wild – and they still multiply wins by 2X. However, all wins are also multiplied by 3X – regardless of whether a wild symbol is involved in the win or not.

Even more appealing is that if you manage to form a win using one of the wild symbols, this time they do multiply – so any wins formed using the wild are multiplied by 6X. This is where the game’s real win-potential lies, and if you’re lucky enough to land a 4-of-a-kind or 5-of-a-kind combo of a top-paying symbol and a wild, you’re in for a big payday.

Again, like we see in the vast majority of Microgaming’s slots, it’s also possible to win additional free-spins. In order to re-trigger the free-spins feature, you simply need to land an additional 3, 4, or 5 of the scatter symbols anywhere in view.

Doing so will award you another 15 free-spins, and there’s no limit to the number of times the bonus round can be retriggered, meaning – potentially – you can spin indefinitely.

However, from my personal experience (and I’ve played the original version of Thunderstruck a LOT), it’s pretty rare to get a retrigger in the first place, so don’t hold your breath!

Gamble Bonus

Any win during the base-game (and, after the free-spins bonus, the entire amount you’ve won) can be gambled by pressing the “Gamble” button. If you opt to do so you’ll be taken to a new screen where you’ll see two options. Firstly, you can guess whether the face-down playing card is red or black. If you guess correctly, you win double your bet amount.

You’ll also notice, however, that you can also guess which suit the playing card will be. If you choose this option, and are correct, your win will be multiplied by 4X. You can gamble up to 5 times in a row, or until the maximum gamble limit is reached; whichever comes first.

Jackpot and How To Win

Thunderstruck is one of those games where it’s almost impossible to give an “exact” jackpot amount. Due to the fact that the bonus round is (theoretically) unlimited – meaning you can keep getting re-triggers and winning more spins, it’s hard to give an upper limit on how much you can win.

Certainly, from what I know of the game, it’s pretty uncommon to get hits upwards of 1,000X – although during the free-spins it is possible to hit those 2-3,000X wins, but they’re rare and seldom come.

Thankfully, the base-game can produce some decent-sized wins too, especially if you manage to line up a 5-of-a-kind combo of the top symbol with one of the wild symbols.


Thunderstruck slot logo Pretty much the only area where I feel Thunderstruck falls a bit short is with the software used. Many online casinos still use the original Flash version of the game (which is very likely to be phased out at the end of 2020), and this can prove problematic for mobile users.

It is possible to play Thunderstruck from your mobile devices, but it’s no easy feat – and you may find that it’s simply too difficult/too much hassle to really get into it.

I’d personally recommend playing Thunderstruck from a computer or laptop. Thunderstruck II, on the other hand, is fully mobile-optimized, and can be enjoyed from virtually all mobile phones and tablets.


Thunderstruck may not get played that often – and I think it’s fair to say Microgaming’s sequel, Thunderstruck II, is a substantially better game.

However, for players looking for a classic 9-liner with some serious win-potential, it’s well-worth giving the original slot a try.

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The bonus round doesn’t seem too hard to trigger from my experience, and it can produce some healthy-sized wins, so if you fancy trying something a bit different, don’t be afraid to try it out for yourself!

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Alex Smith
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Last Updated on February 21, 2021