- For the level before the v1.8 update, see Sky City - Day 20 (Pre-1.8).
In normal mode, the player has to defeat level 1 zombies.
Just by looking at the Choose Your Seeds screen, the zombies that make up the majority are Zombie Fighters, with very few regular Pilot Zombies. The player will have a hard time killing Zombie Fighters because of its high health and fast speed. Spinnapples and slowing plants are almost required to beat this level. The pre-planted Saucer Squash will also help the player since while it can't be used to stun zombies on the sky, its Plant Food effect is similar to Iceberg Lettuce's. If the player does not have Spinnapple yet, Infi-nut's Plant Food effect will do.
- The small number next to the zombie icon means that zombie will always appear in that lane, with 1 being the topmost lane and 5 being the bottommost one.
|Waves||Non-dynamic zombies||Ambush zombies||Note(s)|
|3||None||Carries 1x Plant Food.|
|5||None||Carries 1x Plant Food.|
|7||None||Carries 1x Plant Food.|
|9||None||Carries 1x Plant Food.|
- Start off by planting plants that can take out multiple Zombie Fighters quickly.
- A column of Spinnapples should be planted to protect your ship from Zombie Fighter's bullets.
- Infi-nut's Plant Food effect will also do if you do not own Spinnapple yet.
- If necessary, stun the zombies with Saucer Squash's Plant Food effect.
In hard mode, the player has to defeat leveled-up zombies.
Level 3-4 zombies, particularly the Zombie Fighter, are tough zombies to beat as always. Since there would always be about 3-4 of them appearing every wave after wave 2, strong area-of-effect plants or upgraded plants are necessary for beating the level.
- Use the same strategy you used in normal mode, but with upgraded plants.