Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Played 100 online matches
Completed 'Crossing Over' on hard
Found half of the gold bars
Knocked down 1000 trees
There is no parachute, right?
Destroyed 1000 walls
Completed 'Welcome To Bad Company' on normal
Completed 'Acta Non Verba' on normal
Completed 'Acta Non Verba' on hard
Found 5 unique collectables
Destroyed 200 Walls
Used auto Injector 50 Times
Completed one mission without dying (any difficulty)
Reached Rank 8
Completed 'Welcome To Bad Company' on hard
Completed 'Ghost Town' on normal
Hit hostile helicopter with laser designator
Completed 'Crash and Grab' on normal
Climbed to the highest spot in the game
Completed 'Air Force One' on normal
Killed 25 enemies in a helicopter
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Completed 'Par for the Course' on normal
Found half of all collectables
Knocked down a small forest
Took 3 pictures using the image system
Collected 5 unique dog tags
Completed 'Crossing Over' on normal
Destroyed 50 vehicles. (containing enemy AI)
Reached Rank 3
Played one complete ranked online match
Found one gold bar
Killed 25 enemies
Complete 'Par for the Course' on hard
Complete 'Air Force One' on hard
Complete 'Crash and Grab' on hard
Complete 'Ghost Town' on hard
Find all collectables
Find all gold bars
(Online) Use Squad in the menu, find a friend and play one round
(Online) Have 20 Squad members spawn on you without dying in a single round
(Online) Collect 50 unique dog tags
(Online) Place #1 in a ranked match
(Online) Get at least one kill in every vehicle
(Online) Reach Rank 20
(Online) Reach Rank 25
(Online) 100 kills using vehicle
(Online) Achieve all the awards
(Online) Achieve half of all awards
(Online) Get 10002 kills