Bonuses - it's one more type of upgrade. When play game you can do (or don't) some actions, which can give you some bonus. For example, if after level your base is still alive, you get +50 hit points to your tank for all game. And so on. To see what you get you can in bottom of upgrade window:
Big bonuses
You can "choose" one Big Bonus at one game. There are four Big Bonuses "It's our all!":
  • Wall is our all! - Upgrade level of Base Wall within first 4 levels: wall will have own armor.
  • Armor is our all! - Upgrade armor restoring first 3 levels: at 4th you'll get +2 to armor restoring and rockets reflection ability 50%
  • Mine is our all! - Upgrade number of mines first 4 levels: at 5th mines became friendly for youe team and have additional shock damage. And there will be 15 of them.
  • Rocket turel is our all! - Upgrade number of rockets in Rocket Turel for first 4 levels: 2 rockets will become piercing rockets and one will become homing-mode rocket.
Minor bonuses
Minor bonuses you can get every level:
  • Destroy enemy Rocket turel first - get +3 tries(lives).
  • Pick up 5 and more medikits - every medikit will give +50 of health.
  • Pick up 5, 8 or 10 armor items - tank get +1, +2 or +3% chance get half of damage on every strike.
  • Destroy 10, 20, 30... medikits by gun/chaingun - get +1, +2, +3,... personal medikits [M].
  • Destroy up to 5 enemy rockets by gun/chaingan - get +1 Rocket Storm [R].