Here is the full list of all 76 Iron Marines achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Find the 4 mischievous kids lost in the snow on stage 19.
Have 4 Ranger Squads fighting at the same time in a single Mission.
Kill 50 Alpha Fenrirs during a single try of stage 18.
Help the frozen, weird-looking alien squirrel get his preferred food on stage 18.
Defeat the Fell Bishop in the Spec Op A New Despair in less than 30 seconds.
Complete Mission 4 only deploying Mechas.
Beat Spec Op Into Darkness with all survivors.
Help the space monkeys get the secrets of the Monolith in Mission 4.
Have 100 of your Squads die. They will be missed.
Kill 7000 enemies.
Destroy a total of 46 Raad Carriers.
Target to shoot 9 alien jellyfish until they explode.
Help Sandro unlocks his cowabungous inner self.
Earn a total of 5000 Credits.
Complete a Mission with at least one Brawler, one Shellstorm and one Firewalker at the same time.
Free the cute alien from The Claw's grasp in MIssion 12.
Kill a Spammer before it spawns any Inductors.
Have a Hero reach max level.
Capture all 3 Core Processor's switches without ever losing any of them in Mission 11.
Earn more than 5000 Techpoints.
Kill 343 Peripheroids.
Attack 1000 times with Rocket Towers.
Help the broken Protocol Droid on Mission 10.
Complete Mission 9 without losing a single Squad, like a miniature giant space hamster could do.
Destroy the same Assembly Center 3 times.
Rain down a total of 100 Dropguns to the battlefield.
Extract 10000 Etherwatts.
Complete the Spec Op In Brightest Day with both Power Cores active.
Kill 4000 enemies.
Kill 20 or more enemies in less than 3 secs.
Kill a total of 300 enemies in Emergency Frequency Spec Op.
Teleport all colonists to safety in Spec Op Darkest Hour.
Save the Ambassadress, save the world!
Wake 21 Grimcrushers from their stone slumber.
Kill 17 Etherleeches before they drain your Etherwatts storage.
Spend more than 1987 Etherwatts in a single Mission.
Destroy 11 Fell Refineries.
Destroy 8 Worm Cannons in a single Mission.
Extract 1000 Etherwatts.
Kill 500 enemies.
Have the worm throw 5 Holy Hand grenades at the enemies' faces.
Rescue all 4 wounded soldiers in Mission 3.
Buy any Upgrade from our wonderful selection.
Complete Mission 2 with the COMSAT taking no damage at all.
Complete Mission 1. We knew you could do it.
Click their portrait repeatedly to annoy a Hero during a Mission. They like it!
Save all base colonists in MIssion 5.
Complete Mission 7 without losing any Squads.
Destroy the Fell Bishop's cocoon in less than 4 minutes.
Teleport the five missing Captains scattered in Sagan-1.
Defeat the Fell Tyrant in Normal or Veteran difficulty.
Defeat the Fell Tyrant in Impossible difficulty.
Have at least 4 Brawlers active at the same time in Mission 8.
Deploy any Hero to battle 100 times.
Deploy 77 Empyrean squads onto the battlefield.
Make the Compactors kill 50 Peripheroids.
Spend 10000 Credits at the Arsenal.
Help the Doctor travel through the timey wimey stuff in Mission 11.
Defeat 50 tentacles in Mission 13.
Kill a total of 150 Jackbots resurrected by Oculus.
Defeat Mr: Rob070 in Normal or Veteran difficulty.
Defeat Mr: Rob070 in Impossible difficulty.
Build a total of 149 Towers.
Have 3 Heroes reach maximum level.
Complete all Campaign Missions in Impossible difficulty.
Win Spec Op 'The Last of Them' in less than 7 minutes.
Help the squad of funny penguins achieve maximum coolness on stage 15.
Find the 6 Immensity Stones to awake the awesome Mitten of Tranos.
Destroy a total of 72 Ice Blocks.
Recruit a total of 41 fighters in the Ga’r Warhalls.
Destroy 30 Raad Portals before any enemy can enter our galaxy through any of them.
Search for the ultimate answer buying 42 different upgrades.
Defeat Nexus, the Raad Vanguard Master, in Normal or Veteran difficulty.
Defeat Nexus, the Raad Vanguard Master, in Impossible difficulty.
Complete Spec Op Laser Tag with the prototype Dropgun unharmed.
Beat the Spec Op 'The Colour out of Space' having destroyed all Bishop cocoons in the process.