Metal Arms: Glitch in the System Use General Corrosive in Multiplayer: Once you unlock Corrosive City in multiplayer (which will require 138 chips) go into the main multiplayer menu and press the Edit button. Scroll down to the "Only Vehicles" option, and turn it to "None". Load the Corrosive City map and hit either jump pad in the middle of the map. Go up next few jump pads until you get to the platform with the control console and activate it to get control of General Corrosive.