it's hard as nails aint it? head bottom right and grind out the hard wall, avoiding shots, when lasers or targeted shots prevent you from chomping through there, take some nibbles at the bottom half of the center shield, being careful to destroy as few of the turrets there as possible, destroying them will increase difficulty to a bullet storm... clear a path to the bottom right core and nail it, then clear the remaining blocks on the bottom half of the center core, you can slip a missile past all the turrets and hit the center core if your aim is perfect, after that the top core is exposed and an easy hit.