Here are some tips. I saw that not so many people got the award "Dead on Time", so: 1 - AVOID AT ALL COSTS HUMANS! They give -10secs. This is extremely important. If they are going in your direction, use the horn. If not, try to hit a car, something, BUT DON'T HIT THEM! 2 - Keep your car safe - Don't go in oil marks, don't try to hit soldiers (only if necessary, they don't give time bonus). 3 - Zombies: Try to use your horn when you see a group of them. Try to regroup them. If you can't, give preference for zombies that are eating corpses - They give 3 secs, instead of 2 secs. This is easy guys, i got it on my first time. Just follow those rules, and try to have the car with maximum upgrades, it will help a lot. Sorry if the english is not compreensive.
 "Doomhill"){kind=icon}
 "Infectonator 2"){kind=icon}
 "Stray Cat Strut"){kind=icon}
 "OT Galaxy Episode 1: Kill Tilval 0.1"){kind=icon}
 "Bunny Invasion: Easter Special"){kind=icon}
 "Chronotron"){kind=icon}
 "Homerun In Berzerk Land: Berzerk Ball"){kind=icon}
 "Arkandian Crusade"){kind=icon}
 "Chat In style"){kind=icon}
 "Pong Quest"){kind=icon}
 "SteamBirds"){kind=icon}
 "Throw Rocks at Shit"){kind=icon}
 "Papa's Burgeria"){kind=icon}
 "Road of the Dead"){kind=icon}
 "The Heist"){kind=icon}
 "Flaming Zombooka 2"){kind=icon}
 "Crush The Castle 2"){kind=icon}
 "Gravitee Wars"){kind=icon}
 "Bunny Flags"){kind=icon}