How to destroy a chopper? Boost when there is a ramp then you will do super jump. Control your car while still in the air to the chopper. Hope that helps.
One thing: You are invicible for some seconds after you are dead, at the room where you get 9th key. There's an kitty claw power, make yourself dead and double-jump and tailnado a little to get the kitty claw power.
Back row is make you had a little more defense, but makes your attacks weak. Perfect for people with weak weapon. Front row is make your attacks strong, but makes your defense a little low. Perfect for people with strong weapon.
*Watching a artillery coming to my defense line since the beginning* OMG! How can I won this round ?!. *Watching an bazooka missile shoot the artillery* Oh, so the artillery is not so that strong.