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.
Complete all Campaign Missions in Impossible difficulty.
Defeat Nexus, the Raad Vanguard Master, in Impossible difficulty.
Destroy a total of 72 Ice Blocks.
Defeat Mr: Rob070 in Impossible difficulty.
Defeat 50 tentacles in Mission 13.
Deploy 77 Empyrean squads onto the battlefield.
Have 100 of your Squads die. They will be missed.
Make the Compactors kill 50 Peripheroids.
Defeat the Fell Tyrant in Impossible difficulty.
Help the Doctor travel through the timey wimey stuff in Mission 11.
Have at least 4 Brawlers active at the same time in Mission 8.
Complete Mission 4 only deploying Mechas.
Have the worm throw 5 Holy Hand grenades at the enemies' faces.
Complete Mission 7 without losing any Squads.
Free the cute alien from The Claw's grasp in MIssion 12.
Help Sandro unlocks his cowabungous inner self.
Win Spec Op 'The Last of Them' in less than 7 minutes.
Complete Spec Op Laser Tag with the prototype Dropgun unharmed.
Teleport all colonists to safety in Spec Op Darkest Hour.
Destroy the Fell Bishop's cocoon in less than 4 minutes.
Build a total of 149 Towers.
Recruit a total of 41 fighters in the Ga’r Warhalls.
Defeat Nexus, the Raad Vanguard Master, in Normal or Veteran difficulty.
Destroy 30 Raad Portals before any enemy can enter our galaxy through any of them.
Find the 4 mischievous kids lost in the snow on stage 19.
Have 3 Heroes reach maximum level.
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.
Find the 6 Immensity Stones to awake the awesome Mitten of Tranos.
Kill 20 or more enemies in less than 3 secs.
Destroy a total of 46 Raad Carriers.
Spend more than 1987 Etherwatts in a single Mission.
Spend 10000 Credits at the Arsenal.
Complete a Mission with at least one Brawler, one Shellstorm and one Firewalker at the same time.
Help the squad of funny penguins achieve maximum coolness on stage 15.
Beat the Spec Op 'The Colour out of Space' having destroyed all Bishop cocoons in the process.
Search for the ultimate answer buying 42 different upgrades.
Kill a total of 150 Jackbots resurrected by Oculus.
Have a Hero reach max level.
Defeat Mr: Rob070 in Normal or Veteran difficulty.
Kill a Spammer before it spawns any Inductors.
Kill 7000 enemies.
Deploy any Hero to battle 100 times.
Capture all 3 Core Processor's switches without ever losing any of them in Mission 11.
Kill 343 Peripheroids.
Help the broken Protocol Droid on Mission 10.
Extract 10000 Etherwatts.
Earn a total of 5000 Credits.
Complete Mission 9 without losing a single Squad, like a miniature giant space hamster could do.
Destroy the same Assembly Center 3 times.
Defeat the Fell Tyrant in Normal or Veteran difficulty.
Attack 1000 times with Rocket Towers.
Earn more than 5000 Techpoints.
Defeat the Fell Bishop in the Spec Op A New Despair in less than 30 seconds.
Beat Spec Op Into Darkness with all survivors.
Rain down a total of 100 Dropguns to the battlefield.
Kill 4000 enemies.
Teleport the five missing Captains scattered in Sagan-1.
Complete the Spec Op In Brightest Day with both Power Cores active.
Kill a total of 300 enemies in Emergency Frequency Spec Op.
Save the Ambassadress, save the world!
Wake 21 Grimcrushers from their stone slumber.
Kill 17 Etherleeches before they drain your Etherwatts storage.
Save all base colonists in MIssion 5.
Help the space monkeys get the secrets of the Monolith in Mission 4.
Destroy 11 Fell Refineries.
Have 4 Ranger Squads fighting at the same time in a single Mission.
Destroy 8 Worm Cannons in a single Mission.
Extract 1000 Etherwatts.
Kill 500 enemies.
Target to shoot 9 alien jellyfish until they explode.
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!