The first thing you have to do to complete stages is choose a good character. I would recommend Warthog(the tank). Then after you begin, keep a close waych on the radar. Scroll through attacks according to the stage. Use the nitrous only when you need to escape and use first-aids only when you need them(as they don't come so easily, try to keep enemies away also.
To beat Roadkill, move fast and use Homing Missiles.
To beat Twister(the Racing Car) avoid it's twister attack and try to use the Ricochet(bomb).
To beat Slam(The Hydraulic Shovel) move as far as possible and use any kind of missile(though I would recommend power).
To beat Axel stay away from it's magnetic attacks and use the Napalm.
To beat Grasshopper, attack as fast as you can(you can also use the nitrous to ram into it.
To beat Thumper, stay away from it's fire attacks, but if you can't, ram into it while you're on fire, as he will catch fire also.
To beat outlaw, stay away and use Napalm or Fire(missile).
To beat Spencer, move as close as possible(as it's missiles follow you, no use dodging, if you move close, you get more accuracy) and use the most powerful attack you have.

In the New York stage, don't fall off the roof.
In the lava stage, avoid the lava.
In the Paris-Monumental Disaster level, try firing from rooftops.
In the First Stage, Use your space effectively.
In the Moscow-Suicide Slide stage, fire from above, rather than below.
In the Hong Kong Stage, try blending in with the surroundings.
In the Stage with the fields, collect attacks and use them fast.

That's all! Happy blasting!!!!

To enable several ace codes tap in these whilst in the game.

up,up,left=jumping bean

up,up,right=shields

left,right,up=freeze missile

right,left,up=super napalm

left,right,down=rear fireing

right,left,down=mine

donated by pughy

see ya!!!