Arriving at Vandenberg
When you are dropped off on the roof of the Vandenberg compound, you'll be greeted by Carla Brown. She mentions that the base is under lockdown because of hostile bots. There are four of them patrolling on the eastern edge of the building - if you have a ranged explosive weapon, you could hit them from the roof but that may be an expensive or inaccurate tactic.
There are three routes from the roof. One involves breaking a glass window and dropping onto a lamp rail in the front atrium, and a second involves jumping onto piping on the western edge of the building. Both of these are damaging.
The intended route requires taking the stairs inside, and using the elevator. The elevator is guarded by two MJ12 troops, but has an upper vent that can be accessed by a ladder.
To help take out the four robots, you can release two robots from the hangar. To do so, you need to activate two generators - one is in the first floor in the compound, on the north-west corner of the first floor, and the second is outside on the south-west corner, next to a water tower. Enter the code provided by Carla, 5868 on both generators. When you reach the hangar, press the two buttons next to the doorways to release the robots.
When all four are destroyed, head into the comm building. The scientist will inform you to proceed through the tunnels to retrieve the command center key.
Enemies in this area are mostly robotic spiders.
There are a few possible routes. If you want to go by the ground, expect to encounter mini-spiders and a run through a radioactive area. There is a route in the ceiling above that is safer.
Near the end of the tunnel is a room with a bridge. Since you can't cross it, you need to head into the control room (either by jumping down or by the stairs), and adjust the elevator to floor 3.
Cross the bridge for the last mini-spider. You should also find the key to the command center next to the scientist.
When you enter the command center, speak with Dr. Savage. After a short discussion, the doors to the computer room will open. The safest way to clear it is to walk behind the computers and bypass the electric panel at the back. Take the lift to the second floor, and bypass the second electric panel as well. Login to the computer with the username and password provided, and provide MilNet access to Daedalus.
At this point, you are hit with two plot events. First, Daedalus and Icarus merge to form a new AI, Helios. When you return to Dr. Savage, you will learn from Page that he has captured Tiffany.
Finish up any remaining tasks at Vandenberg, and head to the helicopter at the front of the base.
Abandoned Gas Station
At the road beside the gas station, you can find two people who were forced out of the gas station - in some cases, you may even find Sandra Renton. You can collect the sewer key from them (or from a dead body further along the road), as well as purchase some hardware.
The sewer access is located near your insertion point. Unlock the door on the left, and climb up.
Tiffany is located in the furthest building. There are two guards within that building; a MiB and a regular MJ12 troop. If they are alerted, the troop will activate the alarm, and attempt to kill Tiffany. Eliminate the guards between Tiffany and the nearby junkyard to ensure she escapes.
Rescuing Tiffany isn't required to complete the game, but you will get an augmentation upgrade canister later.
|100||Exploration; entering the elevator shaft from the upper vent.|
|100||Activating the indoor generator|
|100||Activating the outdoor generator|
|50||Exploration: searching under the power generator|
|150||Reaching the robot hangar|
|400||Reaching the comm building|
|400||Getting through the tunnels|
|100||Reaching the chopper at Vandenberg|