Thunderstruck got even better and went multiplayer. You can now Thunderstruck as part of the slots tournament at casinos like 32Red
where all you do is download, if you haven't done so already, pick an alias and simply look for "tournaments" in the games lobby. From there you will see a range of games with different fees (sometimes known as "buy-ins") and start times
Given how popular this game is, it comes as no surprise that you can find it at just about any Microgaming site but as always, it’s good to sign up at recommended casinos that have been vetted. You don’t want to have to sign up and discover that the wagering requirements were so unrealistic, you are never going to be able to cash out.