Here is the full list of all 68 Tannenberg achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Playing as the K.u.K, lose a battle in the Carpathians.
Win 25 Gold Medals.
Kill 25 enemies with artillery as the Entente Powers.
As Frontovik, while crouched, get 3 grenade kills.
Win 10 matches as the Entente Powers.
Switch to other team when asked for autobalance.
Capture an enemy sector alongside 10 or more other people.
Get 50 artillery kills using trench phones.
Get killed by bots 50 times.
Get 7 squad spawns on a single life as NCO.
Be part of the top scoring squad in a match.
Become cut-off in a sector.
Exhaust all your revolver ammo without missing a shot.
Win 10 games as the Central Powers.
Unlock all specializations for the Roumanians
Fight in every weather condition.
Playing as the Infanterie, win a battle in East Prussia.
Kill 4+ enemies in a capture zone.
Unlock all specializations for the Cossacks.
Kick a bot off of a heavy machine gun.
Die from falling down.
Kill 25 enemies with a HMG.
In a single life, take damage from melee attacks and gun shots from a player or players, before being killed by someone entirely different.
Kill an enemy while shooting through an object.
Get a kill while injured.
Unlock all specializations for the Frontovik.
Start a private match.
Cut off at least 3 enemy sectors.
Win a game with a points difference of 100 or less.
Unlock all specializations for the Bulgarians
Unlock all specializations for the Infanterie.
Complete a match on a night map.
Make a successful retreat
Unlock all specializations for the K.u.K. Trupp.
Unlock all specializations for the Latvians.
Kill an enemy soldier manning a heavy machine gun with a head shot.
Kill 25 enemies with artillery as the Central Powers.
Kill 10 people with a heavy machine gun in a single life.
Kill 4 enemies with a single grenade or call in.
Complete a match on a snowy map.
Capture 10 enemy sectors.
Playing as the Central Powers, capture the enemy HQ.
Visit every sector in a Maneuver match.
Playing as the Entente Powers, capture the enemy HQ.
Make 5 kills within the first two minutes of the match.
Kill 3 people with a sabre in an enemy held capture zone.
Check out the credits screen.
Used voice chat.
Damage two enemies with one bullet.
Get killed by your own grenade.
Have your entire squad agree on a vote to change the squad name or type.
Issue 10 command orders.
Be the first to get killed by an enemy in a game.
Complete a match on a foggy map.
Get 10 kills with swords.
Call in Artillery or Recon from a sector.
Used voice commands 50 times.
Kill 5 NCO's in a match.
Club someone to death with binoculars.
Chop off someone's limbs with a sword.
Using a sword, kill an opponent who is also using a sword.
Die 10 seconds after spawning.
Resupply your ammo.
Perform a role switch.
Get a kill from 150m.
Have a look at the overview map.
Get the first kill in a match.
Shoot an enemy while being suppressed or shaken by artillery.