Here is the full list of all 45 Enemy Front achievements.
Kill two enemies with one bullet (Singleplayer)
Help all resistance members in 'French Resistance' mission
Rescue the priest with a single shot in 'First Victory' mission
Kill 10 enemies during 'Loud Sound'
Kill 3 SDKFZ gunners without destroying the vehicle
Take enemy officer/soldier as live shield, then kill 3 enemies
Throw back 3 enemy grenades (Singleplayer)
Kill 25 enemies using mounted HMG (Singleplayer)
Kill 20 enemies using explosive environment objects (Singleplayer)
Collect all secrets
Finish game on Casual difficulty level
Finish game on Medium difficulty level
Finish game on Expert difficulty level
Lure 5 enemies by throwing stones
Collect 5 secrets
Collect 15 secrets
Collect 30 secrets
Paint all Polish resistance symbols on levels that happen in Warsaw
Get into the prison without raising alarm in 'First Victory' mission
Kill an officer and blow up the armory with one shot in 'First Victory' mission
Defend back of the church without using HMG in 'Siege of St. Cross' mission
Destroy all enemy vehicles inside ruined castle in 'Sabotage in the Loue Valley' mission
Set and detonate explosives on the enemy truck in 'Officer hunt in the Loue Valley' mission
Collect all Blyskawica radio station parts in 'PAST Assault' mission
Kill all snipers on top of PAST with a sniper rifle without reloading it
Use commanding officer inside PAST as a human shield
Destroy all vehicles inside the workshop in 'Final Victory' mission
Destroy the cable car in 'Winter in Vemork' mission
Destroy all enemy planes using anti aircraft cannon in 'Fortress at Oscarborg' mission
Rescue Dietrich from POW Camp without raising any alarm
Rescue prisoners from POW camp
Save Home Army soldier in the hospital
Kill 50 Germans and destroy all armored vehicles in 'Home Army Victorious' mission
Collect all rocket parts in 'Fire from the Sky' mission
Kill all enemies inside the V2 factory
Play any Multiplayer match
Perform 100 Headshots in Multiplayer mode
Obtain First Sergeant rank
Play all Multiplayer modes
Win a match in every Multiplayer mode
Play 50 Multiplayer matches
Become the most valuable player in 10 Team Deathmatches
Win a Deathmatch round without dying
Obtain all medals in Deathmatch, Team Deathmatch and Radio Trasnmission modes
Win 5 matches in Radio Transmission mode