Here is the full list of all 23 Deadnaut achievements.
Complete a campaign without destroying a room
Start and complete a mission with a single Deadnaut
Complete a campaign featuring enhanced soldiers with firearms
Unlock all campaign modes
Complete a campaign without losing a Deadnaut
Complete a campaign featuring undead mutants
Kill 100 Type B enemies
Complete a campaign featuring madmen or horrors
Complete a campaign with a rating of Excellent or better
Complete a campaign featuring portals and fast-moving aliens
Kill 15 enemies using hacked Sentinels
Kill a zombified Deadnaut
Kill 200 Type A enemies
Complete the last mission of a campaign with a crew of cloned Deadnauts
Complete a campaign featuring incorporeal entities
Teleport a Deadnaut to another room by entering a portal
Complete a mission without destroying a room
Complete a mission without losing a Deadnaut
Kill 50 Type C enemies
Kill 10 Type D enemies
Rescue a captured Deadnaut
Encounter the ghost of a deceased Deadnaut
Complete a campaign on Extreme difficulty