Dynamic Difficulty was a hidden gameplay mechanic in Plants vs. Zombies 2 and its Chinese version where the difficulty of a level would either increase or decrease depending on the numbers of levels that the player has won or lost. In total, there were six types of difficulties regulated by this system. The following are the types from the easiest to the hardest: SE, E, N, A, H, and T. The values that differed were the number of Plant Food given, along with the number of zombies or zombie types in the level. It should be noted that some levels might not have had a drastic change in difficulty, whereas other levels would become exceedingly easy or difficult after reaching the respective extremes of difficulty. As of the 6.0 update, this mechanic is no longer present, forcing all levels to stay at Normal difficulty at all times.
The victory/loss counter followed a simple system. If the player lost or reset in a level eight times, it would be in the easiest difficulty the next time they attempted a level. However, if the player won in any level eight times in a row, even after the loss streak, the next level would now be in the hardest difficulty. The victory/loss counter would not exceed eight. The following table shows each difficulty type and the number of levels the player would need to win or lose in order to be at their respective difficulty type.
|Difficulty*||Plant Food||Number of zombies||Requirements (levels won)||Requirements (levels lost)|
|SE||α Plant Food given||20% fewer zombies||None||Eight|
|E||α Plant Food given||10% fewer zombies||One||Seven|
|N||α Plant Food given||Normal number of zombies||Two||Six|
|A||α minus one Plant Food given||16% more zombies||Five||Five|
|H||α minus two Plant Food given||30% more zombies||Seven||Three|
|T||α minus three Plant Food given||40% more zombies||Eight||None|
*SE means Super Easy, E means Easy, N means Normal, A means Advanced, H means Hard, and T means Torment.
There were several levels with fixed difficulties. These levels were:
- All Player's House levels
- All Last Stand levels, except:
- All Mummy Memory levels
- All Cannons Away levels
- All Not OK Corral levels
- All Beghouled levels
- Ancient Egypt - Day 1
- Ancient Egypt - Day 2
- Ancient Egypt - Day 5
- Certain Piñata Parties
- Boss levels
- All Vasebreaker levels
- The player could easily abuse Dynamic Difficulty in older versions by simply losing eight times to lower the level's difficulty. However, this was fixed in an update, making it somewhat harder to normally play these levels.