Thunderstruck II

How many bonuses before Thor turns up?

Fifteen. That short answer explains most of what sets Thunderstruck II apart from an ordinary free spins slot. Three or more Thor’s Hammer scatters take you to the Great Hall of Spins, but the Hall does not open all its doors at once. Valkyrie’s round is there from the first trigger. Loki’s joins at the fifth, Odin’s at the tenth, and Thor’s own round arrives only at the fifteenth.

For your first four bonus entries, then, the only choice is Valkyrie. If you load the demo hoping to see the cascading Thor round within a few minutes, you probably will not. It makes more sense to treat this as a slot designed for longer sessions, where the bonus menu grows each time you reach it.

Microgaming released the game in May 2010 as the follow-up to the original Thunderstruck from 2004. That back catalogue is now looked after by Games Global, which is why either name may appear next to it.

Thunderstruck II spec sheet

One note on versions. Some pages using the same name describe a 5×4 grid with 1,024 lines and a free spins wheel. That is not the game covered here, so open the rules screen in the demo to confirm you have the classic 243-ways build.

What shapes a session, most to least

The features below are ranked by how much each one changes what you see on the reels over a session of play.

• The Great Hall of Spins progression
• Thor Free Spins
• Valkyrie Free Spins
• Wildstorm
• The logo wild
• Thor’s Hammer scatter pays

The progression comes first because it decides which rounds you can play at all. Each trigger moves you one step along, and the ladder only goes up. Nothing about past spins makes the next trigger more or less likely. The count simply records how many times you have entered.

Thor Free Spins is where the ladder leads. You get 25 spins with Rolling Reels, so winning symbols clear away and new ones drop into their place, and a multiplier that climbs as high as 5x. It is the only round here that uses cascades, and that makes it play quite differently from everything before it.

Valkyrie Free Spins matters because it accounts for most of your early bonuses. It gives 10 spins with a fixed 5x multiplier on wins. That is simple and easy to follow, and since it is all you will see for the first four triggers, it sets your first impression of the game.

Loki’s and Odin’s rounds are the middle rungs, opening at the 5th and 10th triggers. The paytable in the demo explains how each one works. Read it before you reach them so you know what each round offers.

Wildstorm is a random feature that can turn up to all five reels completely wild. It arrives without needing any scatters, so it is the one large event that does not depend on your progress through the Hall.

The Thunderstruck II logo is the standard wild. It stands in for every symbol except the scatter, and in the base game any win it helps to form is doubled. This happens far more often than Wildstorm and steadily adds to ordinary wins.

Thor’s Hammer earns its own scatter pays as well as opening the Hall, so a trigger spin is not limited to the bonus it leads to.

Reading the return and the risk

The 96.65% RTP comes from independent listings, which broadly agree with one another. The studio has no public game sheet giving a figure. RTP is a long-run average worked out over a very large number of spins. It means that, in theory, every 100 coins staked returns 96.65 over time. It tells you nothing about a single session, which can come out well above or below that.

The 92.05% version matters here. The gap of 4.6 percentage points is large, and the game looks the same in both versions. The rules screen is where the configured figure is shown, so it is worth a quick look.

Listings rate volatility as Medium, and most sites agree. A few rate it higher. In practice, Medium usually means wins of varied size without very long gaps being the norm, but the ladder structure here adds a longer-term rhythm on top of that.

The studio does not publish a maximum win, and the figures quoted elsewhere do not match, so this page leaves that row unfilled. What the game does state clearly are its multipliers: 2x on base-game wins that include the wild, a flat 5x in Valkyrie’s round and a rising multiplier up to 5x in Thor’s.

There is no bonus buy, so the only way into the Hall is by landing the scatters. That is also the only way to move up the ladder.

Related games to try next

Thunderstruck, the 2004 original, makes the obvious comparison. Playing the two back to back shows how much the sequel added in structure.

Immortal Romance also spreads its free spins across four separate rounds, which makes it a useful partner if you like a bonus that changes over time.

Sweet Bonanza offers another take on cascading wins with multipliers, worth comparing with Thor’s Rolling Reels.

Halloween Fortune goes the other way, with a bonus shaped by choices rather than by how many times you have reached it.

Final word on Thunderstruck II

This is a slot that tells you its long-term plan from the start. The base game is plain: 243 ways, a wild that doubles the wins it joins, and an occasional Wildstorm. The real interest is in the Great Hall of Spins and the gradual unlocking of its four rounds.

Play the demo for ten minutes and you will mostly see Valkyrie. Give it a long session on virtual coins and you can work through the whole ladder and judge the Thor round for yourself. Check the rules screen for the RTP before you start, and do not expect a published top prize.