Crysis on delta. Defeat the deck invader

SPOILER

Are you talking about the mothership that you fight on the deck of the aircraft carrier?  

If so i hid behind the crashed VTOL for cover and shot the turrets. After that you'll be jumped by some flying Warriors. Take those out and then keep an eye on the mothership's engines. Once their shields are down blast it with the prototype weapon and then the mothership will go all indepence day on you. That's when you use the rockets located to the left.

Just keep blasting away at the glowy blue light. Then get your ar*e to the VTOL to save you butt.

no haven't got to the mothership yet.  Its the when you first get back onto the deck and there is a large exo-skelenton to fight

Oh yeah the Hunter. I forgot about that part. Just hit it with your rockets and minigun. Then spy chick should shout over the radio that she has weakened..... somehow. Just keep giving it love with bullets and missles in it face and it should fall. If you need a breather just hide under the wind of the VTOl again.