By Odin's beard! Thunderstruck II marks the return of Thor to the world of online pokies, and this time he's brought some friends.

And that's not the only thing that's changed; Thunderstruck II boasts a huge jackpot of almost 2.5 million coins. Thanks, in part, to that figure it's one of the most popular non-progressive slots on the web today.

In 2010, Microgaming launched this much-awaited sequel to Thunderstruck. In Thunderstruck II Thor graces the reels once more, but this time he appears alongside Valkyrie, Loki and Odin, as well as longboats and Valhalla.

The visuals are an upgrade on the original game, with graphics that are more like painted portraits than the cartoon appearance of the original. The first Thunderstruck still looks reasonable, but this is nevertheless a vast improvement.

Players are also greeted by an overture that sounds like it's straight out of Game of Thrones or Lord of the Rings during standard play, which makes this sequel a bit more engaging than the very quiet original title.

Thunderstruck II's gameplay is also an upgrade on the original, though it still takes the form of a 5-reel slot. While the first Thunderstruck pokie had just 9 lines, Thunderstruck II has 243 ways to win. As a result players can expect to enjoy regular wins, although many will be equal to or less than the original bet.

The free spins bonus round has also had been given a serious revamp, with three or more bonus hammers earning players a trip to the Great Hall of Spins. The interesting thing here is that the more you play, the bigger advantage you get in the bonus round.

For the first few times you visit, you get 10 free spins with a multiplier of 5x but from your fifth visit onwards you'll get more spins, extra wilds and extra multipliers. From your 15th visit onwards, you'll get 25 free spins with rolling reels and a multiplier up to 5x.

You can think of this as a sort of loyalty bonus, and it's one that's kept plenty of players coming back to Thunderstruck II time and time again. There's also a mobile version to try if you can't bear to be away from Thor and his pals for too long!

We've written a little above about the way Thunderstruck II rewards frequent players with more generous bonus rounds, and this has to take the crown as one of the main ways the game adds value.

However, we can't ignore the 2.4 million coin jackpot either; this is extremely high for a non-progressive jackpot and will suit players who don't like the risk of progressive jackpots (specifically, them paying out before much cash has accumulated into the pot) down to the ground.

The game may look much the same as the original Thunderstruck, but so much has changed that this game is definitely worth a look even if you haven't played the original in years.

Forget everything you think you know about this game from playing the first Thunderstruck and prepare for a completely new experience. The visuals and theme may be similar in style, but Thunderstruck II's graphics and gameplay are all new. For example, the jackpot on offer is now a mighty 2.5 million coins, there are 243 ways to win and the game boasts several different types of bonus feature that improve based on your loyalty to Thunderstruck II. Whether or not you were a fan of the first Thunderstruck slot, this is one title that's definitely worth checking out.