The main quest is given to you in the form of objectives, however there is a bug in this version that means some important waypoints either disappear prematurely, or never appear at all.

1. Turn on the power
2. Link the elevator to visit the basement. Use the right elevator button to initialise control link, then use the console next to the AZ-5 button to link (the waypoint does not always render). You then have 30 seconds to get to the elevator before it leaves. (Note: you can't link the elevator during a timed event.)
3. Upon return from the basement, there are three consoles that you must obtain 6-digit codes from, and input them in the control room within 60 seconds. They are at: lower hallway next to the elevator, lower foyer by the reactor hall entrance, and in the storage room (opposite to the power room). The keypad to input the codes is at the console with the office chair next to it in the control room.
4. Once all three are linked, the console will show a reactivation prompt for 45 thousand points. Activate this to win the game.

5. Boss fight. You must survive in confined areas and gradually travel through the entire map. The circuit is: control room -> upper hallway -> crossover+storage room+power -> stairwell -> reactor hall -> lower hallway -> upper hallway (via the elevator) -> showers -> control room (see 6).
6. Activate the emergency restart ASAP at the same console that you spent 45 thousand points at. Now you win for real.

Once power is activated, there are three timed events that can occur.
1. Power outage: all lights fail for two minutes
2. Contamination: a section of the map becomes severely irradiated for 90 seconds
3. AZ-5 alert: you have 45 seconds to disarm an automatic AZ-5 activation in the control room. The disarm button is two consoles down from the AZ-5 button (again, waypoints don't always work).

In this version, the overclock bench is in the lower foyer. You can upgrade weapon damage here. In this version, you don't lose your weapons upon death, so this is one of the best investments you can make during gameplay to improve your survival chances.