Saw a video of someone playing this downloadable (31st August) prequel today, and here's the official list of achievements. Surprisingly it's 200 points, like every other arcade title out there.
Still Creek Savior - 20 points
Save all the survivors in Still Creek.
We Ride to Fortune City! - 20 points
Escape Still Creek with Katey.
Chop Shop - 20 points
Defeat Jed the Mechanic.
Zombie Hunter - 10 points
Kill 100 zombies.
Zombie Exterminator - 20 points
Kill 1,000 zombies.
Small Town, Deep Pockets - 20 points
Spend $100,000 in the pawnshop.
Part Way There - 10 points
Find and return a bike part.
Ready to Ride - 20 points
Rebuild the bike.
A Taste of Things to Come - 10 points
Build a combo weapon.
A bigger taste... - 20 points
Build all available combo weapons.
Locksmith - 20 points
Unlock all the doors in Still Creek.
Clueless No More - 10 points
Purchase a clue from Dick, the pawnshop owner.