Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Completed 'Welcome To Bad Company' on normal
Completed 'Acta Non Verba' on normal
Completed 'Crossing Over' on normal
Completed 'Par for the Course' on normal
Completed 'Air Force One' on normal
Completed 'Crash and Grab' on normal
Completed one mission without dying (any difficulty)
Killed 25 enemies
Completed 'Ghost Town' on normal
Killed 25 enemies in a helicopter
Destroyed 200 Walls
Used auto Injector 50 Times
Destroyed 50 vehicles. (containing enemy AI)
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Hit hostile helicopter with laser designator
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
Find 5 unique collectables
Find half of all collectables
Complete 'Ghost Town' on hard
Knock down a small forest
Find all collectables
Find one gold bar
Find half of the gold bars
Find all gold bars
Climb to the highest spot in the game
(Online) Participate in one online match (Ranked)
(Online) Play 100 online matches
(Online) Destroy 1000 walls
(Online) Knock down 1000 trees
(Online) Use Squad in the menu, find a friend and play one round
(Online) Have 20 Squad members spawn on you without dying in a single round
(Online) Collect 5 unique dog tags
(Online) Collect 50 unique dog tags
(Online) Place #1 in a ranked match
(Online) Get at least one kill in every vehicle
(Online) Reach Rank 3
(Online) Reach Rank 8
(Online) Reach Rank 20
(Online) Reach Rank 25
(Online) 100 kills using vehicle
(Online) Take 3 pictures using the image system
(Online) Glide in the parachute for 3 seconds
(Online) Achieve all the awards
(Online) Achieve half of all awards
(Online) Get 10002 kills