In these Brain Busters, the player needs to protect all the endangered plants. Completing a level would earn the player a star before the 1.7 update. After the 1.7 update, the objective is still the same, but only requires the player to progress on the map. If an endangered plant gets eaten or destroyed, the game screen will display "THE ZOMBIES ATE YOUR PLANT!" instead of "THE ZOMBIES ATE YOUR BRAINS!" and the player will fail the objective and the level in a similar manner.
Although the following plants cannot be eaten, they would still yield the game over message mentioned before as if they were eaten.
An endangered Guacodile rushing down his lane eating the row of zombies.
The only time the game over screen is different is in Dark Ages - Night 12, where the text will say "THE PUFF-SHROOMS DID NOT SURVIVE" if the Puff-shrooms disappear normally. Before version 6.9.1, all endangered plants would be set to Level 1 regardless of what level they were supposed to be. As of version 6.9.1, they now matched the player's plant levels.
Save Our Seeds is a reference to the phrase "Save Our Ship" or "Save Our Souls," also known as S.O.S used in emergencies.
The Roman numerals are the level numbers before the 1.7 update for Ancient Egypt, Pirate Seas, and Wild West. For Frostbite Caves onwards, it is used for disambiguation purposes. The parentheses show where the level is located after the 1.7 update, or if the level is removed in the update altogether.
If the player dug up the endangered plants before the 1.9 update, they would fail the objective as if they were eaten. This would occur because the game registers digging up a plant the same way it does when it gets eaten. After the 1.9 update, the shovel no longer has any effect when used on endangered plants.
If an endangered plant is crushed, shoveled (before the 1.9 update), tossed off of the screen, destroyed by Jester Zombie's deflected projectile, stolen by Zombie Parrot, pulled into a space without Lily Pads by Fisherman Zombie (or the plant is pulled onto himself), or burned by a trap tile, when failing the level, the game over screen still says "THE ZOMBIES ATE YOUR PLANT!" even though the zombies did not technically eat the player's plant, they killed the plant in a different manner.
Even though the player's brains are not eaten if the plant is eaten, the brain image is still shown if the player fails.
The endangered plants are placed on yellow and black squares, which is the universal caution sign with diagonal stripes.
In Pirate Seas, if a Zombie Parrot steals an endangered plant, the black and yellow panel is stolen along with that plant.
Not counting Piñata Parties, Far Future - Day 20 and Jurassic Marsh - Day 36 are the only levels with the endangered plants being premium plants.
Sometimes, the brain will not show up if the endangered plants were eaten or destroyed by the zombies. This could be a glitch.
Due to a possible glitch, Wall-nut First Aid does not work on the endangered Wall-nuts in the Wild West Save Our Seeds levels. However, it could have also been implemented as an extra layer of challenge. This works in the Chinese version though.
Also, there are no Key Gates for Save Our Seeds in Kongfu World.
When the player starts a level, they can sometimes see the dirt under the endangered plants from the planting animations.
The endangered tile can be on Lily Pads. It covers the Lily Pad, making them unseen. The only way for this to happen is Fisherman Zombie pulling the endangered Banana Launchers forward in Big Wave Beach - Day 23.
Zombies sent by a Pterodactyl and Prospector Zombies will not die if they are only the zombies remaining in a gameplay, just like on levels with flowers. This was done in order for them to eat an endangered plant from behind.
Even though the plants are described as endangered, one can produce infinite of them using the seed packet, which contradicts the “endangered” part of it.