Event buttons
Use the "Event" button on the indicated stage to get the corresponding result.
Cemetery: Divine ray kills zombies.
Drive-In: Plays music that makes zombies dance briefly.
Military Base: Line of TNT drops down.
Secret Lab: Three lasers rotates around the middle of the level that will kill everything.
Suburbia: UFO abducts zombies.
Woods: Rain slows down zombies; torch is extinguished and cannot set zombies on fire, but can still scare them; zombies that are already on fire remain burning.
Silver medal bonuses
Earn the indicated number of silver medals to unlock the corresponding bonus.
Art: 4 silver medals.
Sepia Vision: All silver medals.
Sketch Vision: 12 silver medals.
Zombie Vision: 1 silver medal.