Portal: System Failure is a community made standalone modification for Portal 2 built on the Source Engine, set within the Portal universe.
In Portal: System Failure, you take the role of test subject #3872 (Bell), as you wake up roughly 15 years after the events of Portal 2. With GLaDOS restored to her full power, the facility is now completely run by various AI with different tasks (personality cores.) As you wake up, you are greeted by the voice of VX-87 (Vixie) - a puzzle designer core and your new testing associate as they guide you through a testing track of their own design. However, something goes wrong with the testing track as a rogue AI hacks into the system and hijacks it. It is now up to you to figure out who is behind the hack and stop them before they can take over the facility.