Doom 3 Walkthrough Intro (2025)

This Doom 3 walkthrough is divided into 27 total pages.1 - Intro2 - Mars City Underground3 - Mars City4 - UAC Administration5 - Alpha Labs Sector 16 - Alpha Labs Sector 27 - Alpha Labs Sector 38 - Alpha Labs Sector 4You can jump to nearby pages of the game using the links above. Intro The opening cutscene plays, with your first taste of the Union Aerospace Corporation. A dropship is on Martian approach.

This Doom 3 walkthrough is divided into 27 total pages.

1 - Intro

2 - Mars City Underground

3 - Mars City

4 - UAC Administration

5 - Alpha Labs Sector 1

6 - Alpha Labs Sector 2

7 - Alpha Labs Sector 3

8 - Alpha Labs Sector 4

You can jump to nearby pages of the game using the links above.

Intro

The opening cutscene plays, with your first taste of the Union Aerospace Corporation.

A dropship is on Martian approach. Three passengers are on board. Elliot Swann, a UAC counselor sent to investigate a rogue scientist on Mars, Jack Campbell, his bodyguard, and a Marine Transfer - you.

The camera pulls back to show this scene on approach. Dr. Betruger, standing at left, instructs his men to send Swann to him immediately.

Campbell and Swann as they exit the dropship.

And here is the main character as he arrives on Mars.

Approach this console to read your first tip. You can use the console to review the Darkstar manifest.

Cooper directs you to reception.

Caseon cautions you to trust no one and to watch your back. He is anxious to leave Mars.

Downstairs is this terminal where you can modify the outbound manifest. Just don't mess with any classified shipments or you'll get this warning.

Back upstairs is this entrance to the facility.

The guard instructs you to stand on one of the bioscan pads.

Pass through the door that the guard opens for you then watch this UAC informational video.

This calendar of events is downloadable to your PDA, which you'll receive in a moment.

Unlocked doors like this one have a green panel. Locked panels are red. This is the only unlocked door available to you, so step on through.

Approach the reception desk for an in-game cutscene. Receive your PDA and your first objective -- report to Marine Command HQ. Stand behind the receptionist and he'll type a supplemental that you are rudely reading what he types!

Download news of a missing scientist from this terminal. You can return to the previous terminal to download the calendar.

Review the information on your PDA (default, TAB key).

Grab this video disk introduction to Mars City.

Proceed up these steps.

You can speak with Chang, but he doesn't have much to say.

Continue down the corridor to trigger this cutscene, a confrontation between Swann and Betruger.

Farther down the corridor, Washington also cautions to watch your back.

Ignore the door on the left for now. Instead, head right into the kitchen.

Watch the TV for some entertaining background.

Pick up the PDA on the counter, you'll need it later. Talk to Tang -- he tells you to work hard and not to poke your nose where it doesn't belong.

Finally some friendly faces. Miller and Marak invite you back for a drink.

This panel will close the shutters and bring up the lights.

In the opposite corner is this game, Super Turbo Turkey Puncher 3. Click on the poor turkey to punch him senseless. Get a score of 25,000 and receive a new email on your PDA.

Seems the HR coordinator was not impressed.

Pass through the door you ignored earlier. Overhear Slang and Kim fretting over weird happenings in the Delta labs.

You can download a request for volunteer test subjects from this terminal.

Proceed through the door marked Marine Command.

Holmes directs you to Sergeant Kelly.

Farther down the corridor you'll encounter Grafton here, plus Creel, configuring that bot in the background, and King, who doesn't want to be bothered. Ignore the "Marine HQ" door for now.

Pass through this door on the left.

Grab this plasma gun video disk to learn of the UAC philosophy of, "Safer worlds through superior firepower."

Pass through another door and continue down the hall. Peer through this Infirmary window for a bit of foreshadowing as this seriously troubled fellow is secured on the examination table.

Return through this door you ignored earlier.

Pass through another door to initiate this cutscene and receive your next objective.

Follow this sentry bot to the elevator that leads to the lower maintenance levels.

As if this introductory level isn't easy enough, now all you need to do is follow this bot. You'll learn to really appreciate these little guys later in the game.