i have done the game with not to many difficulties
Boss Tips:
1. stand on the platform (the big arrow, duh!) and jump over him as he runs, wait untill he returns to his normal position and jump to the lower level, then hammer the shoot key, jump up and continue the sequence.
2. Stand on the very right hand side, as much as possible, turn around, but not to far forward, and u can hit him, but he cant hit u!!
3. jump on his gun(dont run to the right, trust me!!) and wait untill the gun is at its lowest, then jump and shoot his head as many times as poss, do this and he will move forward soon, repeat, then he moves back, repeat still untill he dies. (if u jump up wen the gun is at the top, when u hit the ground he will shoot u)
U defeated the FBI, well done