Complete the following tasks to unlock the corresponding achievement. To view your achievements and stats in Steam, select "Community", then "My profile", then "View all my games", then the game and view stats.

Aviator: Perform car jumps with total distance of 3.14159265 km.
Best Batter Ever: Make the zombies fly over the total of 1212m with your baseball bat.
Chicks Digg the Heroes: Clear the Airport location and save all the hotties!
Dogburger, Anyone?: Kill 5 hyenas with a dynamite.
El Mariachi: Find the guitar case.
Feed the Fishes: Throw 26 dead zombies under water.
Finish Them!: Kill 66 stunned zombies with your baseball bat.
Froggie Style: Perform a car jump over more than 172m.
Hit and Run: Run 192 zombies over with your car.
Home At the Bahamas: Collect 1111 coins.
Homer, J. S.: Make a zombie fly over 33m with your baseball bat.
Hot Rod: Tune up your car to the max.
Killing Machine: Kill 911 zombies with your weapons or your car.
Make It Count!: Finish the Game on Hard Difficulty. Don't be a wimp!
Out of Ammo? Not Me!: With a handgun kill 6 zombies without reloading.
Peace Pipe: Find the Indian drug dealer.
Peacemaker: Blow up the first generator on the farm without killing ANY zombies on the way.
Pound of Ground: Kill 15 zombies within 25 seconds using your firearms only.
Ravioli with ketchup: Exterminate the Mafia family.
Red Lightning: Locate your red car.
Skewer: Kill 4 zombies with a single crossbow shot.
Speed of Light: Hit the speedometer limit.
Surprise in a Barrel: Kill at least 10 zombies by shooting the explosive barrel.
Tough Guy: Kill 68 zombies using any weapons without curing yourself.
U-Baseball: Fight your way through the first underground while using only the baseball bat.
What the Hell?: Reach the game's end within 5 minutes. Yes, MINUTES!