OP

Quoted from pinballguru:

Volatility. This is a term that describes the risk/reward factor. The higher the risk, the higher the volatility. Here is an example: Lets say that the game has a 5-Bank of drop targets. Each completion scores 1 Million Points Plus (1M, 2M, 3M, etc.). This is an example of a low volatility feature. Take the same game and change this feature so that each completion adds a letter to "L-O-N-G-S-H-O-T", then for the rest of ball, each completion scores 10M. I used the word Longshot in the example, because going for this feature could be described as being a longshot. This is an example of a high volatility feature.

Most modern games lack features that have high volatility because the rule set becomes difficult or impossible to balance. Normally when you play a game with a balanced rule set, most of the features have the same difficulty or complement each other. No specific game plan is needed and this leads to a wide variety of features and their outcomes. When you add a high volatility feature to a rule set, this takes the game out of balance because if the player decides to play for the volatile feature, they will ignore the game's other features. So when it comes to designing a game with a deep or broad rule set, the designer needs to avoid adding highly volatile features or for many players, the game becomes a one feature game.