Here is the full list of all 11 ANTIFECTOR achievements.
Kill a dummy trojan in root folder
Play all the gamemodes
Kill a boss
Unlock the saber laser
Unlock the glitch bomb
Unlock the pistol
Unlock 200 max HP
Unlock 200 max ammo
Unlock the powerups
Reach Level 20 or higher in any game mode without taking damage
Play an easter egg