There are a few other slots based on the thunderstruck logic at microgaming casinos now. Beach party is one I can think of, and I think another is coming soon. There's also the other flavor of 9 line bonus slots, skull duggery and big kahuna, these are ok, but I prefer the thunderstruck model myself.
Intercasino has just added some cool new slots, one of which is reminiscent of t-struck. I think its called eastern dragon. I had quite a run on this one over the past 2 days. Its a 20 line
slot that you can play for pennies on up. Its got scatters as well as a bonus game. If you get a dragon on the #1 & #5 reels, it activates the bonus round, 15 free spins. All wins tripled and you can re-bonus during the spins (been there, done that!). This game played pretty loose for me, I started with $100 and played at the 10cent level first of all and pretty quickly turned that into $300! Hit a couple of dragon spins (btw, the dragon is also wild and doubles payout on a non-bonus hit). W/d $200 and played for a while longer, up down up down and stopped for the nite with $100 still in there. Came back the next nite and played it again, this time at the $.05 level and got it up to $200 again, which I cashed out $100 and kept playing that and other games till I was out. (had the $$ in neteller in a day)
Another very creative slot they added is Cash Caper. This one is unique and comes in 2 varieties, $0.25 and $1 denominations. The .25 version is MUCH looser than the $1, but has far less potential for making a good profit. Lots of fun though. Its a multi reel (6 from what I can remember, with 1 more on each end that don't count) slot with pictures of actual US coins (on the .25 version) and currency (only on the $1 version). The money is split in half and in order to win something the 2 halves have to match up to form a complete coin/bill. You win whatever matches up. Pretty ingenious idea in my opinion. I've never seen anything similar, particularly with real money for symbols. The max coin you find on the .25 game is the golden dollar, and the highest payout I got on any spin was about $2.25 or so. Its 3 lines, so max bet costs .75 and there is a bonus game where you pick a vault and get some kind of prize from .50 up to a few dollars ($3 biggest I got). If you also find a key in your vault, it opens the big vault and you get a number of free spins from 1 - 10 I think it was. Almost every spin on the .25 version won some money, but not the same on the $1 version. BUT the prizes are much bigger on the $1, with coins up to $1 and bills from $1 to $100! I actually got the $100 bill at one point when I was down about $50-60. The bonus games came far less frequently and pay all over the place from a couple of dollars up to $25 in my experience. Never got the free spins, so don't know what that does.
Another one to check out if you play at any RTGs is Super Diamond Mine. I like that one for nickels, once you get to the bonus game you can really clean up (won over 2000 nickels in the bonus last time I tried it at nostalgia).