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