Here is the full list of all 34 Battlefield 3 achievements. It takes around 100-120 hours to unlock all of the achievements on Windows.
Transported a flag carrier in an air vehicle in CTF
Destroyed the Gunship
Won one round of Tank Superiority
Received one of each ribbon in the game
Got a kill with the skid loader
Got a kill with the following weapons in a single life: Assault Rifle, Jet, Tank
Got a kill with each of the following vehicles: the BTR-90, DPV and F-35.
Fell over the edge on Ziba Tower
Got 10 kills with each of the ten Back to Karkand weapons
MVP in a ranked match
Got 10 kills each with Tank destroyers and Mobile Artilleries
Destroyed an enemy vehicle using the xbow
Got a kill from the passenger position on a motorcycle
Received all 3 vehicle warfare ribbons
Found the secret reptile
Took your first enemy Dog Tag
Without dying, got a kill with xbow, primary weapon, and hand grenade
Completed a round of Gun Master
3rd MVP in a ranked match
Got one kill with the Quad bike
Received all 4 support efficiency ribbons
Unlocked all xbow parts
Picked up 50 weapons in Scavenger mode
Rank 45 achieved!
Took a swim in the Oman Hotel swimming pool
Won a round in Conquest Domination
Got 10 kills with all ten CQ weapons
Got one kill with the Gunship
Received all 4 weapon efficiency ribbons
Killed an enemy after successfully paradropping a vehicle
Without dying, got a kill with a Carbine, Pistol and Rocket Launcher
Destroyed an air vehicle using the AA jeeps
Captured one flag while playing CTF
2nd MVP in a ranked match