Assault Suit Leynos

Nox is the large walking boss at the end of the stage. It has 3 parts - the box-like structure at the back, the huge gun turret hanging underneath, and the body itself. After destroying the gun, the game gives you the ability to go to the right and enter the transport ship, but if instead you keep shooting Nox until it is completely destroyed you will earn this trophy. You will almost certainly earn this just from playing through the stage normally. (It took me forever to realize that entering the ship was even an option.)