Here is the full list of all 20 Soldier Front 2 achievements.
Revive 25 fallen allies
Get 25 kills with SGs
Destroy an Alien Controller in Hero mode
Destroy a turret in Hero mode
Buy from the Hero Mode shop
Kill a Xanthid in Hero Mode
300 headshots
Get 25 kills with SMGs
Get 300 Assists
Use MGs for 10 hours
Get 25 kills with MGs
Get 550 total kills
Get 75 headshots with ARs
Get 25 Assists with SRs
Get 450 deaths
Attain the rank SGT (rank 20)
Play 10 hours
Reach 10 hours in Xanthid modes
Kill 2500 Xanthids in hero mode
Get 50 kills in Hero Mode