From versions 1.7 to 5.2.1, the player could get one World Key after beating the Gargantuar level in any world.
In the 5.1.1 update, the Gargantuar statue holding the World Key in every world except Ancient Egypt was removed to prepare for the "Keysplosion" of the 5.3.1 update which has the player receive a key chain containing 10 world keys, allowing all worlds to be accessed after completing Ancient Egypt - Day 8.
In the previous updates of the Chinese version, a World Key could be obtained by either beating the last Day in the first three worlds, or by beating the level before the first boss level in the rest (Day 16 and Day 30 in Kongfu World, Day 29 in Far Future, Night 30 in Dark Ages, and Day 30 in Big Wave Beach and Day 25 in Frostbite Caves, Day 24 in Sky City and Day 25 in Lost City). They were removed in the 1.8 update and the worlds are unlocked with stars again.
Additionally, a free World Key is given to all players since the 3.5.1 update to the 5.3.1 update as a reward for beating Ancient Egypt - Day 2. This key was won for all players by YouTuber ZackScottGames when he completed a Piñata Party challenge set by the PopCap team.
Before the 5.3 update, every player would still have spared two keys after beating all 11 worlds. However, as of 5.3 update, if the player has beaten Day 8 of Ancient Egypt, he/she will always have his/her remaining amount of keys subtracted to zero.
It can be used to unlock any world, according to the description. Therefore, the player can go to any world in any order they want to. It is recommended to unlock easier worlds first before unlocking harder ones to make it easier to advance.
- The player can only get more World Keys if the player decides to purchase a world instead of using a World Key, getting a free World Key, or unlocking Pirate Seas after beating Ancient Egypt - Day 12 for a limited time during April 2014 since the player didn't need to use the World Key.
- Each Gargantuar statue that is present in each area holds a World Key.
- From Lost City and onward, all Gargantuar level statue designs are different, now being a sculpture of the Gargantuar's fist holding the World Key.
- The advertisement for World Keys claim that the player will find Gargantuars in Day 8 of each world. However, this is not true in Dark Ages and later worlds.
- In earlier versions, there was a glitch in which the player could randomly receive a large number of World Keys. This was fixed in a later update.
- The key chain from which the player receives all the World Keys-or, the "Keysplosion," as PopCap Games calls it, it only has four World Keys on it, despite there being more than four worlds.
- The key chain also consists of: a pot charm, a Sunflower charm, a L.E.A.F. symbol key, a car key, a bottle of Hot sauce, and an antique key.
- The car key could possibly be the same key the player obtains after completing Level 3-4 in the first game. The key belonged to Crazy Dave and was used for his van that housed Crazy Dave's Twiddydinkies.