- Not to be confused with World Key.
Keys are items available in Plants vs. Zombies 2 and Plants vs. Zombies Online. In versions before the 1.7 update, the player needed them to open gates, and therefore gain access to certain upgrades, plants and Brain Busters levels. In the 8.9.1 update, they are used to unlock new worlds. There are different variations of keys for each world in Plants vs. Zombies 2. However, in Plants vs. Zombies Online, there was only one type of key, the Tower Defense Key.
Keys were removed from Plants vs. Zombies 2 in the 1.7 update and from the Chinese version of Plants vs. Zombies 2 in the 1.8 update. A new method of unlocking plants and rewards replaced the original layout. Any keys the player had before the update were turned into coins.
In the 8.9.1 update, keys returned and are repurposed. Instead of unlocking gates, they are used to unlock new worlds, replacing World Keys. Beating Ancient Egypt - Day 6 will grant the Pirate Seas Key, while the rest can be obtained by beating Dr. Zomboss in the previous world.
In Plants vs. Zombies Online, keys were mainly obtained by beating levels for the first time in Adventure Mode. Subsequent replays of the beaten level would not give the player any more keys.
How to obtain
Keys were found as a rare dropped item from all zombies killed in a time zone. The odds of a zombie dropping a key were relatively low, around one percent off of any zombie, regardless of health or speed. Keys could also be found off of the Treasure Yeti every once in a while, and a lunchbox could carry three keys of the area the Yeti was killed in.
- Killing the Treasure Yeti was one of the best ways to get keys, as every other lunchbox had three keys.
- Killing zombies, but keys had a very low drop rate
- Completing Piñata Parties could result in a few keys being rewarded.
- Daily log-in rewards from the monthly reward calendar (Chinese version only).
Plants vs. Zombies 2
Plants vs. Zombies 2 (Chinese version)
Plants vs. Zombies Online
- Each gate required three to five keys to be unlocked, except for the Special Delivery gate in Ancient Egypt, and Bronze Matrix gate in Kongfu World which both required only one key.
- In the pre-1.7 versions of Plants vs. Zombies 2, Piñata Party piñatas had a chance to carry one key for any area, as long as the player had that area unlocked.
- The maximum number of keys that could be stored at a time was 99; any more collected would not increase the counter past the maximum.
- Prior to the 8.9.1 update, if the player had used World Keys to unlock worlds but made no progress on them, a glitch would occur wherein they would have the trophy for that world despite not completing it yet. This can lead to getting more than 1 trophy of the same world.