Multi-player levels:
Earn a bronze or better medal in a single player level to unlock it in multi-player mode.
Silver medal bonuses:
Unlock the following bonuses by earning the corresponding amount of silver medals:
BONUS – SILVER MEDALS
Zombie Vision – 1 silver medal.
Art – 4 silver medals.
Sketch Vision – 12 silver medals.
Sepia Vision – All silver medals.
Event buttons:
Use the “Event” button on the following stages to get the corresponding effect:
STAGE – EFFECT
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.
Cemetery – Divine ray kills zombies.
Suburbia – UFO abducts 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.
Steam achievements:
ACHIEVEMENT – HOW TO UNLOCK
Brain Surgery – 100 Brains sucked.
d6 Admires You – All Gold medals.
d6 Commends You – All Bronze medals.
d6 Respects You – All Silver medals.
Dynami-Te-He – 1000 Zombies blown up.
Extinction – 100,000 Zombies killed.
Friend of Bruce – All levels unlocked.
Friend of d6 – All Developer medals.
Graduation – Complete zombie academy.
Hot To Trot – Last 30 seconds with 50 zombies on fire.
Murder On The Dance Floor – 1000 Zombies sent dancing.
Paint The Town Red – Fill the screen with the maximum amount of blood on any level.
Red Shirt – Kill the away team Zombie.
Texas Style – 100 chainsaw combos.
Tourist – All Arcade levels unlocked. ?