Defcon 5

The main gameplay involves navigating through the complex in first-person view, shuttling between manned turrets outside to shoot down waves of fighters and scouring base levels for card keys during downtime. You'll also need to use the "Virtual Operating System" to repair damage, monitor intruders, and place robot sentries to guard key passages.

As you progress, you can increase the software's efficiency to command turrets remotely or set them to auto-attack with a high degree of success. This allows for more time to search the levels for keys and ultimately leads to your goal: finding the clearance to self-destruct the base, defend your escape shuttle, and get out alive.