Let them in? They might help (+2 $/s) or be infected!
Lvl 1: 500 HP
Shield that absorbs all dmg first.
Next: Steel (+Max HP)
Increases safe zone size.
Provides passive income.
Level: 0 (Max 20)
Massive income boost during day.
Level: 0
Heals player & cleanses infection.
Flat multiplier to all building HP.
Rapid but weak fire.
Balanced defense.
Slow fire, massive range.
Heavy damage dealer.
Freezing shots slow enemies.
Chains damage to 3 targets.
Retaliate against base attackers.
Damages zombies that walk over.
Reinforce structure (+100 Max HP).
Moat that slows enemies. Adds bridge.
Extreme slow, minor damage.
Explodes when stepped on.
Heavy cover block (High durability).
You survived 0 seconds.