Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Got 10002 kills
Achieved all the awards
Completed 'Ghost Town' on hard
Reached Rank 25
20 Squad members spawned on you and you didn't die!
Reached Rank 20
Achieved half of all awards
100 kills using vehicle
Completed 'Crash and Grab' on hard
Completed 'Air Force One' on hard
Completed 'Par for the Course' on hard
Completed 'Crossing Over' on hard
Completed 'Acta Non Verba' on hard
Completed 'Welcome To Bad Company' on hard
Climbed to the highest spot in the game
Completed 'Ghost Town' on normal
Hit hostile helicopter with laser designator
Found all gold bars
Found all collectables
Completed 'Crash and Grab' on normal
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 one mission without dying (any difficulty)
Completed 'Par for the Course' on normal
Found half of the gold bars
Found half of all collectables
Completed 'Crossing Over' on normal
Completed 'Acta Non Verba' on normal
Destroyed 200 Walls
Used auto Injector 50 Times
Found one gold bar
Completed 'Welcome To Bad Company' on normal
Found 5 unique collectables
Knocked down a small forest
Killed 25 enemies
Played 100 online matches
Got at least one kill in every vehicle
Knocked down 1000 trees
Collected 50 unique dog tags
Destroyed 1000 walls
There is no parachute, right?
Took 3 pictures using the image system
Used Squad in the menu, found a friend and played one round
Reached Rank 8
Placed #1 in a Ranked Match
Collected 5 unique dog tags
Reached Rank 3
Played one complete ranked online match