Just find out the right method and its gonna b eZ
This game doesnt require much skill. All you need is to use the right method:
Always press the down-button. If an angent ducks as well and shoots at you, jump to not get hit. keep on shooting moving to the right. As soon u see a agent at the left shoot 2 bullets on him an turn right again.
On the first robot you have to use a routine. U gotta find that out ur self...
On the helicopter just stand as right as possible and the bombs wont hit you. All you have to do is shoot upwards and heli will rush into ur bullets.
and on the final robot, stand on his cannon and jump to hit his head. He will smack u, but u wont lose a live.
have fun :)