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