As Peter has pointed out, there is an interesting die mechanic in this game known as the Doubling Die (DD). Essentially, whenever you make a roll, you will roll the DD as well. The DD is a special 16-sided die, marked with lots of 1s, a bunch of 2s, a few 4s, two 8s and one 16. When you make a roll, you multiply the roll on the normal die with the result of the DD (don't worry, there's a handy table for the mathematically challenged - we don't want to have to do multiplication in our heads!). If you roll a 16 on the DD, then you roll it again, and continue multiplying. If it comes up a 16 again, keep rolling! This means that you could potentially roll some extremely high numbers - the highest I ever had in my previous game was a roll in the vicinity of 124,000. The system is open-ended. You roll high, you succeed in your task. You roll really high, then you succeed really well.

The DD is also marked with a (c) and a t. The (c) indicates Mental Winds' copyright on the d16, but it also stands for Critical. When you roll a (c), something bad happens. Even if you roll high (multiple 16s) and then a (c), something bad happens. You can succeed at whatever you're doing, but something bad happens. Similarly, the t stands for Tremendous. If you roll a t, something good happens - even if you failed at your task. Most of the time, rolling a (c) or a t is counted as a 1 on the DD, which means that the result up to that point is multiplied by 1 - ie, unchanged.