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