Heart of Steel

Heart of Steel is a moderately difficult level of I, Zombie focusing on the Iron Armor Zombie.

Plants

 * Air Pea
 * Fume-shroom
 * Magnet-shroom
 * Sunflower
 * Peashooter
 * Puff-shroom
 * Umbrella Leaf

Zombies

 * Regular Zombie (50 sun)
 * Pole Vaulting Zombie (75 sun)
 * Buckethead Zombie (125 sun)
 * Bungee Zombie (125 sun)
 * Iron Armor Zombie (225 sun)