The majority of the achievements in Defense Grid 2 are very simple and progression based. Meaning you just unlock them in time like kill 100 aliens and beating the story.
Alien Tears – 10gs – Earn a gold medal on every mission in Story mode.
Annihilator – 10gs – Kill 10,000 aliens.
Play-through the campaign and you will be well on you way. Either way, just play the game and in time you will unlock it.
Arsenal – 10gs – Build 20 towers of any type in one mission.
Play the first level of the game, or any level with at least 20 pieces to drop towers, and drop all guns or boosts in the 20 locations to unlock the achievement.
Base Defender – 100gs – Complete the single player campaign in Story Mode.
Complete all the levels in story mode. Simply play through and beat each level.
Boot Camp – 10gs – Finish all the missions in Chapter 1 in Story Mode.
There are just three levels in the first chapter. Play all three of them and you will unlock it.
Brothers In Arms – 10gs – Earn a Bronze (or better) medal in a Coordinated Defense Multiplayer mission.
Play a mission in coordinated defense mode and complete a level with at least a bronze. By beating the level you will get the achievement because you will automatically get at-least a bronze.
Burn Baby Burn – 10gs – Build 100 Inferno towers.
Inferno towers shoot out flame throwers towards the aliens. Build a total of 100 to get the achievement.
Close Call – 10gs – Save a core that is less than 10 seconds away from the map’s exit point.
When an alien makes it to your base, he tries to escape back out of the map with a core piece. Kill the alien and the core will return to the base. If you kill the alien within 10 second of him escaping you’ll get the achievement.
Confident – 10gs – Use the speed up control at 3x for a total of 60 seconds in any mission.
Press RB to fast forward the level. Keep it fast-forwarded for 60 seconds.
Death From Above – 10gs – Use the Orbital Laser Special Weapon (General Cai).
Diversity – 10gs – Build at least 1 of each tower type in any single mission.
Eradicator – 10gs – Kill 100 aliens.
Kill 100 aliens, you will get this achievement at the end of the first level.
Exterminator – 10gs – Kill 1000 aliens.
Kill 1000 aliens, you will get this after playing 5+ levels.
Field Promotion – 10gs – Earn a silver (or better) medal.
Filthy Rich – 30gs – Win a mission with at least 10,000 resources remaining.
Firebug – 10gs – Using only Inferno towers, Win any Chapter 4 (or later) mission.
First Blood – 10gs – Kill 1 alien.
Flawless Victory – 10gs – Earn a Gold Medal.
Don’t let a single alien take a core piece back for a whole level. Just play level one and block and upgrade the towers.
Full Defense – 10gs – Build 50 towers of any type in one mission.
Full House – 10gs – Build and fully upgrade each tower type in one mission.
Full Potential – 10gs – Win a chapter 4 (or later) mission with level 3 towers only and no selling.
Go Team! – 10gs – Earn a Gold medal in a Coordinated Defense Multiplayer Mission.
Go To Your Home – 10gs – Use the Core Teleport special weapon (Professor Taylor).
Great Ball of Fire – 10gs – Build 100 Meteor towers.
Gun Crazy – 30gs – Using only Gun towers, Win any chapter 4 (or later) mission.
Happy Returns – 10gs – Recover a loose core.
Head Trauma – 10gs – Build 100 Concussion towers.
Hey! That’s mine! – 10gs – Kill an alien carrying a power core.
High Voltage – 10gs – Build 100 Tesla towers.
Build a total of 100 Tesla towers.
If At First You Don’t Succeed, Retry Again – 10gs – Use the reload checkpoint option five times in a single mission.
Indecisive – 10gs – Sell 10 towers or more in a single mission.
After building a tower, you can sell them away for a small amount of resource and to free up space. Do this 10 times in a single mission.
Kaboom! – 10gs – Build 100 Cannon towers.
Build a total of 100 Cannon towers.
Leadhead – 10gs – Build 100 Gun towers.
Build a total of 100 Gun tower.
Liquidator – 10gs – Sell 10 towers.
After building a tower, you can sell them away for a small amount of resource and to free up space. Do this 10 times.
Master Builder – 10gs – Use the command shuttle to move 6 map sections in Mission 6.
Master Strategist – 100gs – Earn 100 Gold Medals on any missions.
Minimalist – 10gs – Using only level 1 towers, Win any Chapter 4 (or later) mission.
More Please – 10gs – Use the Resource Reinforcement Special Weapon (Professor Briel).
No Fast Blast – 10gs – Use the Temporal Cannon Special Weapon (Colonel Rissler).
No Sale – 10gs – Win any mission without selling any towers.
This is easiest to do in level 1. Simply place a tower that blocks the one path, making the alien trip much longer. And place towers surrounding the path for the aliens and take them all out without ever selling a tower.
Not So Fast – 10gs – Build 100 Temporal towers.
Build a total of 100 Temporal towers.
Now With Sprinkles – 10gs – Enable a Tower Augmentation item on any tower.
Penny Pincher – 10gs – Win a mission with at least 5,000 resources remaining.
Pew Pew – 10gs – Build 100 Laser towers.
Planet Defender – 30gs – Earn a silver medal (or better) on all missions in the Story mode.
Pumped Up Towers – 10gs – Use the Tower Overcharge Special Weapon (Advisor Zacara).
Retry – 5gs – Use the Reload Checkpoint option.
Salvage Rights – 10gs – Kill an alien boss creature. (Juggernaut, Rumbler, Turtle, or Crasher)
Shell-shocked – 10gs – Using only Cannon towers, Win any Chapter 4 (or later) mission.
Shoot That Guy – 10gs – Use the Precision Targeting Special Weapon (Rear Admiral Phillips).
Surplus – 10gs – Win a mission with at least 1,000 resources remaining.
10 Items No less – 10gs – Enable a Tower Augmentation Item on 10 Towers.
Thanks for Playing! – 5gs – Earn a Bronze (or better) medal in a Single Player Mission.
The Not-So-Friendly Skies – 10gs – Build 100 Missile towers.
The Path Most Traveled – 10gs – Win a Gold medal on Mission 19 without using the Command Shuttle.
Tower Expert – 10gs – Build every tower and every upgrade for each tower.
Warning Shots – 10gs – Play a DG Fighter Multiplayer mission.
What IS that? – 10gs – Inspect 10 aliens.
Winning Shots – 10gs – Earn a Victory in a DG FighterMultiplayer mission.
Would you like a boost with that? – 5gs – Build 100 Boost towers.
Xenocide – 30gs – Kill 50,000 aliens.
Yellow Beats Green – 5gs – Upgrade a level 1 tower to a level 2 tower.
Master Siege Breaker – 55gs – Survive 100 waves on any Super Grinder challenge mode.
Siege Breaker – 55gs – Survive 100 waves on Grinder challenge mode on any mission.
Untouchable – 30gs – Beat a Chapter 4 mission or higher with zero cores captured.