Averagely, it’s supposed to pay back 96.65% of money but in a long-long run. In my case, after every 100 spins made, my balance jumped from -$17.84 to +$72.35 as seen on the graph that you’ll find in my Thunderstruck 2 review of the slot. Overall, I even made $30 on it. So, I can recommend it as a truly paying machine.