The Purple Matrix, found in Bionic Commando: Rearmed, is a key that opens a door in the Fissure I area of Bionic Commando. Look for the Purple Matrix Door (it glows purple) as you swing through the cave. It's on the left. Inside you'll find some old school Bionic Commando music blaring out of a radio and a comfy chair. There's also some sort of museum exhibit of what appear to be spider robots. Whatever!