You are Alfred(Phrédo)Robrtson, an elictrical engineer who helped to construct the Aperture power-grid as well as wire GLaDOS into it. Kept on-site in case of emergency you were forgotten by the now deceased employees as well as GLaDOS*. You are woken up by your containment unit in its final moments of back-up battery life and you alone explore and escape while finding clues piece by piece about the past and present of Aperture Science. You are the Escapist.
How nice, everything is a swamp now.