In Dead Island (1), every time that you landed a critical hit with an elementally modified weapon on an enemy, the elemental effect would be applied. Among the elemental effects, there are fire, shock, impact, poison, fire, and bleeding.
In Dead Island Riptide, this is certainly not the case. It seems that when that an elemental effect is applied and when that you critical hit, are independent variables. What's the algorithm for when the elemental effect is applied? Secondly, how can the elemental proc rate be improved?