Here is the full list of all 70 Get Off My Lawn! achievements.
Kill 250 tanks with the shotgun
Kill 10,000 grunts with the shotgun
Collect 2500 orbs in a single game
Kill 10,000 grunts with the musket
Kill 250 behemoths with the ray gun
Kill 5000 grunts with the ray gun
Kill 100 tanks with the ray gun
Kill 500 behemoths with the shotgun
Kill 1000 enemies on the last lawn square
Kill 500 dodgers with the shotgun
Kill 250 dodgers with the ray gun
Reach level 15
Spend 50,000 orbs
Kill 10 tanks with the ray gun
Kill 1000 grunts with the shotgun
Kill 500 grunts with the ray gun
Kill 25 behemoths with the ray gun
Kill 500 behemoths with the musket
Get a score of 20000
Kill 25 tanks with the shotgun
Kill 50 behemoths with the shotgun
Spend 10,000 orbs
Kill 500 dodgers with the musket
Don't fire once
Use a last stand
Collect 1000 orbs in a single game
Kill 25 tanks with the musket
Reach level 10
Kill 50 dodgers with the shotgun
Kill 1000 grunts with the musket
Kill 50 behemoths with the musket
Kill 25 dodgers with the ray gun
Kill 50 grunts with the ray gun
Kill 100 grunts with the shotgun
Kill 100 enemies on the last lawn square
Get all 3 guns
Use all utilities once
Kill 7 enemies during a single cane time
Kill 5 enemies during a single cane time
Kill 3 enemies during a single cane time
View the credits
Use a head start
Spend 1000 orbs
Get a 10x multiplier
Get a score of 5000
Kill 50 dodgers with the musket
Kill 10 enemies on the last lawn square
Kill 100 grunts with the musket
Reach level 5
Get a score of 1000
Collect 100 orbs in a single game
Kill your first alien
Miss 8 times in a row
Reach level 20
Upgrade your house fully
Upgrade your musket fully
Upgrade your shotgun fully
Upgrade your ray gun fully
Upgrade all guns to level 3
Upgrade all guns to max level
Kill 5000 dodgers with the musket
Kill 5000 dodgers with the shotgun
Kill 2000 dodgers with the ray gun
Kill 5000 behemoths with the musket
Kill 5000 behemoths with the shotgun
Kill 2500 behemoths with the ray gun
Kill 250 tanks with the musket
Kill 2500 tanks with the musket
Kill 2500 tanks with the shotgun
Kill 1000 tanks with the ray gun