This will actually need to be a handful (or a lot, whichever) of people.  The first line is a Sentry bot, which is basically minigun toting, rocket launching, nuclear exploding death on wheels.   It doesn't have to match the Robocop voice used in game though, it can be whatever voice you have, so long as it is stiff and robotic.  The others will be smaller robots.  I will literally use every audition made here (for the Dalek chorus), only one person gets to be the sentry bot.  Also, no voice effects will be necessary, I will handle those myself.