This is a cascading slot and each explosion of the wild gives a collapse of a part of the reels and an increase in the multiplier that is applied to the next payout. Another interesting feature is Wild Mining, it gives from 1 to 3 wild ones if the same symbols are collected on a straight line, but they do not bring payouts.
Traditionally, Nolimit City slots offer the purchase of three types of bonus. A more modest version of the bonus round with two rows of symbols costs 60x, and for three and four active rows you will need to pay 157x and 500x, respectively.
The bonus round is similar to the bonus of the famous Money Train from Relax Gaming. Three spins, in which at least one coin must appear, which resumes counting and collects a multiplier or a function located above the reel.