Complete the following tasks to unlock the corresponding achievement. To view your achievements and stats in Steam, select "Community", then "My profile", then "View all my games", then the game and view stats.

Achievement	How to unlock
(See?) I've got this	Kill an entire wave without aid of towers on Medium or higher difficulty.
...You get a Different Machine	Upgrade towers 500 times.
599 US Dollars	Fully upgrade three towers.
A Walk in the pARC	Survive all the waves on Arc on Insane difficulty.
Airborne Assault	Kill 1000 enemies while you're in mid air.
All is Dust	Gib 1337 enemies.
All Pro	Kill 2000 enemies with the sniper rifle.
Automagic	Kill an entire wave without using your weapons.
Bang for your Buck	Kill an entire wave only using the Assault Grenade on Medium or higher difficulty.
Big Game Hunter	Shoot 9 strawberry fishes.
Big Guys Require Big Guns	Kill 1500 Tanks.
Boom! Headshot!	Kill 4 enemies in one Sniper Rifle clip.
Bridge Troll	Survive all the waves on Bridge.
Chill, Man...	Upgrade three Slow Fields to max level.
Close Call	Finish a level with less than 5% Core Life remaining.
Collateral Damage	Kill 15 Runners with one Assault Grenade.
Flawless	Finish a level on Medium or higher difficulty with 100% Core Life remaining.
Flyswatter	Kill 1500 Dodgers.
Fully Covered	Build one of each Tower on Arc.
Giant Enemy Crab	Get 5000 weak spot hits.
Good Day, Mr. Walker	Kill 2000 Walkers.
I Feel Claustrophobic	Survive all the waves on Mine on Insane difficulty.
I Said STOP!	Freeze an enemy in a max level slow field.
If you Replace the Working Parts...	Upgrade towers 250 times.
It's Cool, I've got this	Survive a wave without spending any Resources in previous Build Phase.
Legion	Reach wave 30 on Casual Endless.
Lockdown!	Kill 250 Blockers.
Lunch box	Find the sandwiches on Bridge.
Mach 5	Kill 4000 Runners.
Martyr	Kill an enemy with a grenade while being knocked back.
Meet the President	Meet the President on Arc.
Old School	Complete a level without teleporting.
Over 9000!	Reach wave 10 only having built Blocks and Lightnings.
Perfectionist	Finish a level on Insane difficulty with 100% Core Life remaining.
Pollen Allergy	Kill 2000 spore pods.
Reanimator	Teleport 200 times.
Rymndhaest	Kill 1000 Hoverers.
Safe at Last	Survive all the waves on Arc.
Scatter Brain	Reach wave 10 only having built Blocks and Scatter Lasers.
Seven Sisters	Find the Babushka Doll on Mine.
Shift's Over	Survive all the waves on Mine.
Shoot 'em in the head!	Kill 250 bobble heads.
Spray and Pray	Reach wave 10 only having built Blocks and Gatlings.
Terminated	Kill 3000 enemies with the assault gun.
The Bigger they are...	Kill 250 big walkers.
The Monument	This is a secret achievement, can you unlock it?
The Plot Thickens	This is a secret achievement, can you unlock it?
This isn't the Golden Gate!?	Survive all the waves on Bridge on Insane difficulty.
Time to Expand	Kill 100 Soakers.
Too Fast	Kill 1000 Chargers.
Turbo Aim	Kill 300 Gliders.
Voyage au centre de la Terre	This is a secret achievement, can you unlock it?
Without Number	Reach wave 12 on Hardcore Endless.
You shall not PASS!	Build 50 Block Towers during one Build Phase.