Dynamic Difficulty was a hidden gameplay mechanic in Plants vs. Zombies 2 and its Chinese version where the difficulty of a level will either increase or decrease depending on the numbers of levels that the player has lost or won. In total, there are six types of difficulties regulated by this system. The following types are from the easiest to the hardest: SE, E, N, A, H, and T. The values that differ are 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 may not have a drastic change in difficulty, whereas other levels will 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 follows a simple system. If the player loses or resets in a level eight times, it will be in the easiest difficulty the next time they attempt a level. However, if the player wins in any level eight times in a row, even after the loss streak, the next level will now be in the hardest difficulty. The victory/loss counter will not exceed eight, so if the player wants to lower or increase the difficulty, they should win or lose eight times. 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 respected 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 are several levels with fixed difficulties. These levels are:
- 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 previous 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.