Here is the full list of all 16 Armored Gear achievements.
Kill the first enemy
Kill 500 enemies in a single game
Kill the boss without getting damage
Get bonus coloring tank
Beat the game 3 times
Earn $ 50,000
Having 200 units armor
Kill 10 bosses per game
Having 300 units energy
Pick up 50 powerups
Beat the game without dying
Dial 1,000,000 points
Kill a boss in less than 30 seconds
Survive with 1 unit armor
Kill 3 enemies with one shot
Kill an enemy shot rainbow kitten