Immortal

Difficulty: Hard

Immortal is an achievement unlockable on PC if the player has purchased Plants vs. Zombies. Once the player has survived twenty waves and selected their plants for the next round, the player will then have the achievement completed, since it would not be awarded until he or she begins the next round.

Almost every properly-designed setup can make it through twenty flags of Survival: Endless, as the waves only start to become really huge when the player reaches thirty flags or more, especially after thirty-two flags.

Strategies
For strategies, see Survival: Endless/Strategies.

Trivia

 * The picture looks like a flag with a brain on it with the number twenty on the left top corner, as it symbolizes the twentieth wave.
 * This achievement can also be earned by accessing and surviving for twenty waves in other Survival: Endless games on the Limbo Page.