Here is the full list of all 28 Interstellar Marines achievements.
Reach 4,000 Training Points
Eliminate 100 Combat Training Robots on Realistic Difficulty
Reach 2,000 Training Points
Reach 1,000 Training Points
Complete Welcome Tutorial Mission
Reach 7,000 Training Points
Reach 10,000 Training Points
Reach 15,000 Training Points
Reach 25,000 Training Points
Reach 50,000 Training Points
Reach 100,000 Training Points
Reach 200,000 Training Points
Pick up The Gift to become the T-IM101
Terminate the T-IM101
Collect All Audio Logs in The NeuroGen Incident
Complete Realistic Difficulty in The NeuroGen Incident in Co-op
Complete Realistic Difficulty in The NeuroGen Incident in Single Player
Eliminate 1,000 Combat Training Robots on Realistic Difficulty
Eliminate 500 Combat Training Robots on Realistic Difficulty
Complete 100 Elimination Challenges on Realistic
Complete 100 Survival Challenges on Realistic
Complete 100 Escape Challenges on Realistic
Complete 100 Successful Revives After Death from Robots or Opposing Team
Complete Starcrown Aerospace on Realistic in Co-op
Complete Starcrown Aerospace on Realistic in Single Player
Exit Hell Week with +10.000 Combat Points
Open a Supply Drop Crate in each Hell Week Zone
Eliminate 500 CTRs in Hell Week