Go 2 the level metropolis fight through until you get 2 the scarab, THIS SHOULD ONLY BE DONE IN CO-OP,kill the aliens on top it and jump down on top the bottom left leg. Go and hug the scarab and jump slightly till u can c inside and stay there. Have player 2 go down the ramp inside and run back on top 2 the catwalk, then blast those aliens 2 bits!!