Thunderstruck Slot: Free Spins & Bonus Offers in 2022

Thunderstruck II was the much-anticipated sequel to the Thunderstruck slot in 2010. 12 years later, the online slot machine continues to be offered across the US. As always, you can find out why the game is in demand and how you can claim your free spins with the help of the CasinoSmash team!

The most recommended US slot sites are outlined underneath, but if you don’t want to spend a cent, you can play for free via the demo mode.

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Thunderstruck Slots: Game Overview

Thunderstruck Free Spins

The Thunderstruck slots are members of the Microgaming family, a leading casino service provider from the UK. From that alone, you know the gameplay is going to be exciting and engaging because Microgaming is notorious for leaving gamers on the edge of their seats. Their online slots don’t disappoint, and Thunderstruck II is no exception.

What you’ll notice straight away is the HD graphics that introduce the game’s main characters. There’s an impressive soundtrack, too, helping to cement the Norse mythology theme. But the coup de grace is the number of pay lines as the Thunderstruck slot machine is equipped with 243 ways to win.

Although Thunderstruck II doesn’t contain any progressive jackpots, we don’t believe this is an issue. The top prize of 8,000x your stake and an RTP of 96.6%, this highly volatile slot is a lot of fun. This five-reel, three-row slot game has a total of eight bonus rounds to try and unlock, adding to the suspense.

Online Slot Info Sheet

Thunderstruck II has remained popular since its release in 2010. Not many real money slots can boast the same thing, other than the likes of Starburst. The key to the gameplay is the free spins feature where a multi-level Free Spins bonus feature rewards players with as many as 25 free spins.

However, before we get into bonus rounds and how to trigger them, let’s focus on the game’s fundamentals. Below is a table we recommend reading as it outlines everything you should know about Thunderstruck II.

Slot NameThunderstruck II
Created ByMicrogaming
Release Date2010
ThemeNorse Legend
RTP Rate96.6%
Volatility LevelHigh
Maximum Bet$15
Minimum Bet$0.30
Max Win8,000x Stake
Max Cash Win2.4 million credits
Free Spins BonusAvailable
Demo Free SpinsAvailable
Mobile VersionYes

Game Theme

We were impressed by the slot's theme because there’s something enjoyable about Odin, Thor and Loki, especially as they’ve become part of popular culture thanks to other media. Thunderstruck II is a lot sharper than its predecessor, the original Thunderstruck slot.

For example, Microgaming has introduced an extra four bonus features to make sure the theme is detailed. Plus, there’s a better chance to collect big wins since you can create an additional winning combination.

How to Play the Thunderstruck Slot Machine

Free Spins offers to play Thunderstruck Online

Microgaming has kept things simple to allow players to easily follow the gameplay on Thunderstruck II. During the base game, you can try to form wins by hitting successful sequences of three or more symbols.

There can be as many as five in a winning combination, and it must begin from the first reel on the screen. Collecting three Thors on reels one, two and three, for example, awards you with a multiplier. Land five and the multiplier will increase to 16.66. Thor’s Hammer is the highest-paying symbol and the Viking Longship is the lowest-paying of the symbols.

The number of coins staked is easy to control through the arrow buttons at the bottom of the screen. Once you’ve decided on a suitable coin value for your stake, just hit the spin button to kickstart the reels. The reels automatically calculate wins and award wins instantly after they have stopped spinning.

Base Game Symbols

The good news is that all the Thunderstruck game symbols are available in the base game to use to form wins. In fact, they are essential since wilds and scatters trigger the free spins bonus round, providing you with a chance to improve your real money rewards.

Continue reading to find out more about the Thunderstruck II symbols to watch out for when you play online:

  • Thor
  • Odin
  • Loki
  • Valkyrie
  • Valhalla
  • Viking Longship
  • Thunderstruck II logo (wild icon)
  • Thor’s Hammer (scatter)

Keep an eye out for the scatter symbol because it has a 200x multiplier when it lands on an active pay line, meaning big wins are possible.

Bonus Symbols and Features

Special features and a bonus game or two are waiting for you behind every corner in this Microgaming offering. Some are general to the industry, whereas others are synonymous with the Thunderstruck game series. Either way, the following are central to unlocking free spins and much more!


Winning combination on Starburst slot machine

The wild symbol substitutes for all the symbols barring the scatter, making it potentially profitable if you are fortunate enough to form a winning combination with Thor’s Hammer. When it does sub in for lower-paying symbols, it automatically doubles your earnings too. The only exception is during the Wildstorm feature.

Wildstorm Feature

When you play Thunderstruck slots, certain features will activate at random. The Wildstorm feature in Thunderstruck II falls into this category because the round can appear out of the blue. If it does, Thor will use lightning to transform the reels into wild reels. Get five during Wildstorm and it’s possible to claim the 8,000x maximum win.

The Great Hall of Spins

Again, Thor’s Hammer is central to this bonus offer as at least three will activate the mini-game. During the game, additional scatters come with multipliers up to an amount of 200x. Thunderstruck II’s Great Hall paves the way to the bonus features below, too:

  • Valkyrie Free Spins – The Valkyrie bonus is available between your first and fourth bonus feature spins. 20 free spins are on offer, as well as a 5x multiplier and a top prize per spin of 1,383x your stake
  • Loki Free Spins – Only eligible on your fifth Great Hall trigger. Loki awards 15 free spins and the game’s max win
  • Odin Free Spins – On your 10th trigger, Odin appears bearing a gift of 20 extra turns. Plus, his ravens transform symbols into additional multipliers at random
  • Thor Free Spins – If you can get into the Great Hall 15 times, Thor is waiting to greet you with Rolling Reels feature. This is where wins are boosted by 2x, 3x, 4x, and 5x, depending on the combination

Volatility Level and RTP

Our Thunderstruck II slot review found that the game is a high volatility online slot, but it is described as medium to high volatility by some operators. What this means is that the Thunderstruck II game can pay out big wins in a short space of time if you are lucky. The slot game is eligible for real money wins as well, but game weighting applies. The return to player percentage is considered above average as anything over 96% is healthy.

Thunderstruck vs Thunderstruck II: Main Differences

These casinos offer free spins on Thunderstruck II

Even on the surface, there are quite a few noticeable differences between the Thunderstruck slots. Both are well-designed and very popular, but Thunderstruck II incorporates more modern elements to help enhance the user experience.

As soon as you load the games, you’ll notice the visuals are more defined in the sequel. Thunderstruck has a cartoon feel, whereas Thunderstruck II is sharp and slick. The number of ways to win is greater in the latest release. Thunderstruck’s return to player percentage is lower, too.

An area where the original is superior to the sequel is the maximum win. It's almost four times bigger compared to the sequel. Lastly, some of the symbols have been tweaked. For instance, Ram symbols aren’t scatters on Thunderstruck II. Indeed, they aren’t available whatsoever.

  • Ways to Win - 9/243
  • RTPs - 96.1%/96.6%
  • Max Wins - 30,000x/8,000x

What US Casinos Offer Thunderstruck Slots?

Do you want to make your first deposit and play for real money? In that case, it’s important to learn about the US casino sites that host the Thunderstruck series. These are online casinos that have brilliant promotions that might boost your cash funds. Remember that a deposit might be needed.

  • Bet365 - NJ
  • DraftKings - CT/MI/NJ/PA/WV
  • BetMGM - MI/PA/NJ
  • Borgata - PA & NJ
  • FanDuel - CT/MI/NJ/PA/WV

Some of these casinos offer a demo version of the game, so you can try out this and other free slots without having to make a deposit.

Other Video Slot Machines to Try

The great thing about the Norse mythology theme is that it’s entertaining. So, it’s not surprising that other developers have selected games that also use the genre to appeal to casino players. If you like Thunderstruck II and want to win free spins and much more, these are the slot machines to sample:

  • Age of the Gods Norse: Gods and Giants
  • Viking Gods: Thor and Loki
  • Viking Fire
  • Vikings Go Berzerk
  • Vikings Go Wild
  • Thunderstruck
  • Gates of Valhalla
  • Viking Runecraft

If you'd like to stick with the same game provider, Microgaming has a multitude of amazing options for you to choose from, including King Tusk, Immortal Romance, Avalon, and others.

Alternatively, if you want to spice up your experience, you can try a host of new slots. There's no better place to start than the most popular slots in the US.

To help you find all the best games available in the United States, we prepared specific lists like this 88 Fortunes free spins collection or these offers to play the Texas Tea slot, Sugar Parade and Fishin Frenzy for free and win real money prizes.

Frequently Asked Questions about Thunderstruck Slots

When did the two Thunderstruck slots launch?

Thunderstruck launched in 2004 and Thunderstruck II launched in 2010. They are two of Microgaming’s oldest and most successful real money casino games, which is why you can find them at a range of online casinos in the US. Check out the “What US Casinos Offer Thunderstruck Slots?” section for more info.

What are RTP rate and volatility level of Thunderstruck?

Microgaming states that the RTP rate for Thunderstruck II is 96.6%, and that’s considered better than average for modern. However, it’s worth remembering that the number is theoretical as the house edge can change depending on several factors. Thunderstruck II is a medium to high volatility game.

Is Thunderstruck a popular slot machine?

This particular slot is considered one of the best slot games ever because of the simple gameplay that’s easy to follow and the fantastic bonus rounds (Thunderstruck II has double the number of bonus features of Thunderstruck). To capitalize on the series’ popularity, Microgaming released Thunderstruck Wild Lightning in 2021 to critical acclaim.

Can you cheat on Thunderstruck online?

No. Online casino regulations are strict to ensure the gameplay is fair. For example, underage gambling is banned. The introduction of advanced software, such as a random number generator, also makes cheating challenging. Finally, slot machines are games of chance, meaning there’s no way to influence how the reels spin.

Is Thunderstruck a loose slot machine?

It depends on your timing. Thunderstruck II is a highly volatile slot, which means it doesn’t pay out regularly. But when it does, you can receive big wins on numerous occasions. Therefore, catch it right and the Thunderstruck games might payout real money.

Can I win a progressive jackpot on Thunderstruck?

There are no jackpots of any kind on Thunderstruck II. Instead, the game uses various bonuses to engage players and enhance the gameplay. These can be anything from bonus spins to real money prizes. The key is to unlock the bonus mini-games using wild symbols and scatter symbols.

Who made Thunderstruck?

Microgaming made Thunderstruck, Thunderstruck II, and Thunderstruck Wild Lightning in 2004, 2010 and 2021. Most of its services are developed for mobile devices, with the entire Thunderstruck franchise compatible at Android casinos and Apple casinos. Microgaming was founded in 1994 and is based in the Isle of Man in the UK, but it sells its products to operators worldwide, including the US.

Is Thunderstruck available in the United States?

Yes, Thunderstruck is available in the US at eligible online casinos. These include Bet365, BetMGM and Borgata. For a full list, head to “What US Casinos Offer Thunderstruck Slots?” for the operators and the states where they operate.

How many free spins are there in the Great Hall of Spins in Thunderstruck II?

There are tons of free spins in the Great Hall of Spins feature. You can aim to retrigger entry into the Great Hall as many times as possible to boost the number of free spins you’re awarded. For example, gain entry 15 times and you’ll trigger the Thor Free Spins round where 25 extra turns are waiting for you, as well as Rolling Reels’ multipliers.

BioA passionate writer who likes to play games at casinos online and live. While I have worked for the last four years in FinTech, EdTech and Digital Marketing industries, I wrote many high-quality reviews for games on various websites, which also gave me the idea to work in this industry and explore more.
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