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