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