Sky City - Day 25 was the 25th and final level of Sky City in the Chinese version of Plants vs. Zombies 2, from versions 1.6.0 to 1.8.0 in the iOS version. After completing this level, the player received a World Key.
It was inaccessible without hacking, and it contained the unfinished Zombot Vulture Fighter boss battle. When clicking on the level, the game would display a message stating that all the stars in Sky City had to be collected to make it playable. However, it remained locked even when all stars had been collected. The level was never finished as a result of Update 1.8 to the game and was removed and replaced. Sky City - Ultimate Challenge is the completed current playable form.
- The player also received a world key from completing the previous level, thus making Day 25 the second level in a row to grant a key, and the second world to grant 2 world keys (after Kongfu World) in this version.
- Far Future - Day 30 was also only accessible via hacking before Update 1.8.
- * A gate can be unlocked with a key after completing this level
^ Conjectural name