I don't consider myself a great gamer but I think I am above average. I can hold my own on COD, Rainbow etc but this has got me!!!

I have tried twenty times, I just cannot defeat Shockwave. Everything I tried fails, and the hints on the net are useless. Can anyone PLEASE help!? PLEASE! I don't even come close to beating him really, his health is always at about 50% by the time I die.

Thanks.