In the level "little resitance", do everything you are supposed to do until you get to the beach. starting at the far right side of the beach there are holes. as you make your way leftwards across the beach jump into each hole. once you're in the last hole stay in there. after a couple of seconds, the music will change and the screen will shake and you'll hear weird voices. after that these black stone cats come from the ground. each one, when you walk up to it, will have a hand sign on the screen. walk up right to the front of the cat and hold X untill your weapon changes to ray gun.

(p.S. swith you ray fun with pistol, that way you'll have a heavy gun and a pistol gun.)