Here is the full list of all 21 TANKBOX achievements.
Have a high number of bullets in the box
Have a high number of mines in the box
Push a green tank into their own bullet
Save your comrade from a direct shot
Kill 8 tanks in one level without wasting a shot
Beat level 21
Beat level 50
Beat level 100
Place a mine the moment before you die
Beat the game without dying
Get to level 5 without shooting or placing a mine
Barely dodge a mine explosion
Destroy 314 tanks with a direct hit
Destroy 314 tanks with a ricochet