GRAD is a rather tough UG. He will start out at the far end of the room and you'll have to sprint from cover to cover to get there. Stick to the side of the GRAD and attack it from there. Get close and start swinging but be prepared for GRADs counter attack. As long as you stay close, the missiles and bullets will go over your head and if you can successfully parry GRADs melee attacks, you can beat him back to the next section of the room. Secondary weapons will have no effect.
Once you've been GRAD to the next area, he'll change forms into a walking Gear. The strategy at this point is actually quite similar though with a bit more movement. Get close and start attacking and when you see the fits move up and outward, be prepared to parry. It will move in almost any direction and attempt to get distance so it can use it's various ranged weapons. When it does, you'll need to start a Ninja Run to deflect bullets and avoid the rockets that it will fire. Get close again and as you deal damage, you'll get the chance to cut off the various panels. Continue pushing the attack and you'll have it defeated in short order.
