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Game help · Tips & secrets

Immersive Sim · First release 1999

System Shock 2

Main campaign, deck transitions, key mission puzzles and keypad codes. The tutorial section gives build guidance.

WindowsPlayStation 4PlayStation 5Xbox OneXbox Series X/SNintendo SwitchNintendo Switch 2

Guide chapters
9
Puzzle and code entries
22
What this guide covers

Main campaign, deck transitions, key mission puzzles and keypad codes. The tutorial section gives build guidance. Original 1999 campaign and 25th Anniversary Remaster. Console availability refers to the remaster.

Story routes, decisions and endings may contain spoilers. You can show or hide marked sections.

Search for puzzles, codes and locations across games

Check your edition

Editions & platforms

EditionPlatformDifferences & notes
1999 / 25th Anniversary RemasterWindows, PlayStation 4, PlayStation 5, Xbox One, Xbox Series X/S, Nintendo Switch, Nintendo Switch 2Original 1999 campaign and 25th Anniversary Remaster. Console availability refers to the remaster.

Training and Deck 2 · Med/Sci

After training, you wake on the Von Braun. Take the wrench and the log for the cryo exit. 45100 opens the main route and 00000 opens the optional cryo closet. Recharge the power cell and insert it at the entrance to Medical.

Look near Biopsy for Grassi's Crew access card. It gets you into the Crew area to follow Dr. Watts' trail. His log is beside the broken surgical unit in Research & Development. Enter 12451 to open the maintenance route to Engineering.

An early Standard ranged weapon is useful for a first run. Plan at least one Research level for the Hydroponics objective. Activate accessible reconstruction stations and keep separate saves before risky minigames.

Deck 1 · Engineering and main elevator

Find the log containing 15061 on the upper east side of Cargo Bay 2B. Open Engineering Control, read the clue by the Fluidics computer, and use 34760 in Auxiliary Storage 5 to collect part 45m/dEx. The optional Utility Storage 4 opens with 59004.

Fit 45m/dEx in Command Control and start the flush from the Fluidics computer. Proceed to Engine Core and reset both engine nacelles. Reset main power to restore the elevator. On the way to Polito, the biomass obstruction stops the elevator at Hydroponics.

The later 94834 self-destruct code belongs to the end of the Von Braun sequence. Use it when the data link on Operations sends you back.

Deck 3 · Hydroponics and Toxin-A

Collect Toxin-A from the office near your arrival point. Start researching it and supply the requested chemicals from the storeroom when prompted. You need two samples of antimony (Sb) and one sample of vanadium (V) in total.

After research finishes, insert one vial into each of four environmental regulators. In B/C, check the icy area below the ladder and then the regulator beyond the damaged lab in C. The regulator in the icy area also has the access card for Hydroponics A nearby. Continue through the other sectors for the remaining regulators and watch the mission update after each use. All four regulators are needed to clear the elevator shaft to Operations.

Deck 4 · Operations and simulation units

Follow the objective to Polito's office. Then collect the override chips for the three simulation units and match them to their respective machines. The Interpolated Simulation Chip goes into the Interpolar Simulation Unit on the lower Power Ops level. Save outside. Approaching the unit opens side doors containing Annelid Arachnids.

The story moves between Operations, Recreation, and Command. Collect the Ops Override card on Command and return to the sealed Command Center on Operations. Establish the data link there. The lower level can also give you the log for the Med/Sci sub-armory and its 98383 code. The Operations armory uses 13433.

Deck 5 · Recreation and distress signal

Four art displays show the fragments [1, 4, 10, and 6]. Check the lower floor of the Bon Chance Lounge, artechnology upstairs in the TriOp Galleria, the upgrade terminal lobby, and the easternmost room in the north row of the upper crew quarters. Treat 10 as two digits and send the distress signal with 14106.

The billiards room east of the Bon Chance Lounge holds the log for 34093. For the crew quarters room marked 11111, the clue is on the counter at the Sensual Stimulation Units. The other two locks are the reception safe at 12345 and the security room at 50220.

Deck 6 · Command, shuttles, and backtracking

Take the Ops Override card on Command for the Operations data link. After the Command Center authorizes you, return to Engineering's Engine Core and set the overload with 94834.

For the shuttles, collect the access card from the security area in the Officers' Quarters. Code 83273 opens the security room. Operate the shuttle controls, lower the shields, and destroy the shuttles. The hacked replicator can supply the Sympathetic Resonator for the shield generator. Back away immediately after installing it.

Once the objectives are complete, the central tram takes you to the Rickenbacker. Recharge equipment and bring a reliable ranged weapon with ammunition. You will need it for small moving targets in later boss rooms.

Rickenbacker · Black eggs and gravity

Destroy all 16 black eggs with glowing veins on the route through the first section of the Rickenbacker. If the count is short at the exit, check the location list in the puzzle card. SHODAN reports your progress.

Look for gravity controls and access cards on bodies if a route ends. After dealing with the eggs, proceed through the bridge and escape pod into the Body of the Many.

Body of the Many · Brain and shield nodes

Follow the organic passages to the large boss chamber. Keep moving and destroy the Psi Reaver brain structures along the sides if you need relief. Three orbiting shield nodes provide the brain's actual protection.

Shoot all three nodes from range, then fire on the exposed brain. Enemies remain dangerous after it dies. Climb onto the stump and jump into the opening to follow the tunnel to the finale.

Finale · SHODAN

Story details & possible consequences

Use the last upgrade stations before entering the bridge. Follow the altered station to the spiral descent and jump across the platforms to the vent. Save before dropping into the arena.

During the fight, hack the terminals around SHODAN or use an ICE Pick at each terminal. With enough ammunition, you can also shoot through the shield layers. Keep moving when the avatar closes in and use your ranged weapon on SHODAN once the shield falls.

Cryo exit · 45100

Med/Sci · Cryo

New Code is on the nearby body.

Show solution

  1. Step 1

    Enter 45100 at the matching keypad.

Cryo closet · 00000

Med/Sci · Cryo

The optional closet uses five zeroes.

Show solution

  1. Step 1

    Enter 00000 at the matching keypad.

Maintenance conduit · 12451

Med/Sci · Research & Development

Read the log at the broken surgical unit.

Show solution

  1. Step 1

    Enter 12451 at the matching keypad.

  2. Step 2

    The conduit leads to Engineering.

Sub-armory · 98383

Med/Sci · Armory

The clue log is on the lower floor of Operations' Command Center.

Show solution

  1. Step 1

    Enter 98383 at the matching keypad.

Utility Storage 4 · 59004

Engineering · Utility Storage

The Utility Storage 4 message gives the code.

Show solution

  1. Step 1

    Enter 59004 at the matching keypad.

Engineering Control · 15061

Engineering · Cargo Bay 2B / Engineering Control

Locked In is on the upper east side of Cargo Bay 2B.

Show solution

  1. Step 1

    Enter 15061 at the matching keypad.

Auxiliary Storage 5 · 34760

Engineering · Auxiliary Storage

Fluidics Backdoor is by the Engineering Control computer.

Show solution

  1. Step 1

    Enter 34760 at the matching keypad.

  2. Step 2

    Collect 45m/dEx for Command Control.

Engine Core overload · 94834

Engineering · Engine Core

The later Operations data link provides the number.

Show solution

  1. Step 1

    Enter 94834 at the matching keypad.

  2. Step 2

    Wait for the overload objective if you want to see the preceding story events.

Armory · 13433

Operations · Armory

The No Shirkers clue is between the bulkhead and lounge.

Show solution

  1. Step 1

    Enter 13433 at the matching keypad.

Reception safe · 12345

Recreation · Help desk

The safe uses a simple ascending sequence.

Show solution

  1. Step 1

    Enter 12345 at the matching keypad.

Garden maintenance room · 34093

Recreation · Garden

Under the Garden is near the billiards room replicator.

Show solution

  1. Step 1

    Enter 34093 at the matching keypad.

Locked crew quarters room · 11111

Recreation · Crew Quarters

Looking Out for No.1 is by the bar.

Show solution

  1. Step 1

    Enter 11111 at the matching keypad.

Security room · 50220

Recreation · Security

This code belongs to Recreation's security area.

Show solution

  1. Step 1

    Enter 50220 at the matching keypad.

Activate the distress signal · 14106

Recreation · Transmitter

The four art display fragments are 1, 4, 10, and 6.

Show solution

  1. Step 1

    Enter 14106 at the matching keypad.

  2. Step 2

    Activate the transmitter after entering it.

Security room · 83273

Command · Officers’ Quarters

Security Rewired is in the locker beside a poster.

Show solution

  1. Step 1

    Enter 83273 at the matching keypad.

  2. Step 2

    Take the shuttle access card from the security room.

Flush the coolant and restore the elevator

Engineering · Cargo Bays / Engineering Control / Engine Core

45m/dEx is the part needed to restore fluidics control.

Show solution

  1. Step 1

    Open Engineering Control with 15061 and Auxiliary Storage 5 with 34760.

  2. Step 2

    Install 45m/dEx in Command Control. Flush the lines at the Fluidics computer.

  3. Step 3

    At Engine Core, reset both nacelles and then main power.

Research Toxin-A and treat four regulators

Hydroponics · Four environmental regulators

The chemical storeroom and Hydroponics A access card unlock key steps.

Show solution

  1. Step 1

    Pick up the first Toxin-A sample in the office near the elevator.

  2. Step 2

    Start researching and supply two antimony (Sb) samples and one vanadium (V) sample when prompted.

  3. Step 3

    Regulator B is in the icy area below the ladder. Take the Hydroponics A card there. Regulator C is beyond the damaged lab, down the ramp.

  4. Step 4

    Regulator A is in the room with a camera, grub pods, and a Midwife. A corpse by the entrance to A carries a spare vial. Regulator D is at the end of the dark corridor beyond two more grub pods.

  5. Step 5

    Return to the main elevator once the blockage clears.

Simulation units and data access

Operations / Command

Malick set an ambush by the unit in Power Ops.

Show solution

  1. Step 1

    Quantum: The red assassin in Operations B carries the Quantum Simulation Chip. Its simulation unit is in Operations C.

  2. Step 2

    Interpolated: Loot the chip from the red assassin near the broken elevator in Operations C. Insert it into the Interpolar Simulation Unit at the bottom of Power Ops in Operations D. Expect the arachnid ambush.

  3. Step 3

    Linear: Collect the chip from the third red assassin in Operations D. The Linear Simulation Unit is in the next room by Bronson's squad.

  4. Step 4

    After the Recreation objective, collect the Ops Override card on Command and use it at the Command Center on Operations. Opening the data link gives you the Engine Core objective.

Lower the shuttle shields

Command · Shuttle control room

The shuttle access card is in Officers' Quarters security.

Show solution

  1. Step 1

    Open the security room with 83273 and collect the card.

  2. Step 2

    Go to the shuttle controls. If the objective calls for a resonator, hack the replicator and take the Sympathetic Resonator. Attach it to the shield generator and retreat.

  3. Step 3

    Destroy the exposed shuttles and take the central tram onward.

Brain of the Many shield nodes

Body of the Many · Boss chamber

The three orbiting stars sustain the shield.

Show solution

  1. Step 1

    Use a ranged weapon on the three stars. Destroy the Psi Reaver brain structures on the sides if the enemy pressure is too high.

  2. Step 2

    Shoot the brain once the shield is down.

  3. Step 3

    Climb the remaining brain stem and jump into the opening.

Lower SHODAN's shield

Finale · Arena

The terminals provide a quicker route through the shield.

Show solution

  1. Step 1

    Hack the terminals around SHODAN or use ICE Picks.

  2. Step 2

    If you are playing without hacking, use ranged attacks on the shield layers and watch your ammunition.

  3. Step 3

    Evade the avatar and shoot SHODAN once she is vulnerable.

All 16 black eggs

Rickenbacker · Pod 1 up to the Pod 2 transition

Eggs 3, 4, and 8 are visible from a different height or from across the room.

Show solution

  1. Step 1

    1. Climb out of the arrival room and check the corner near the security terminal.

  2. Step 2

    2. Look through the security room window onto the upper level by the large cargo container. The explosive crates provide a useful target.

  3. Step 3

    3. Look up at the ceiling just inside the next room.

  4. Step 4

    4. Shoot across the hull breach from your side. The floor underneath the force field will not support you.

  5. Step 5

    5. Follow the ramp down to the entrance of the red service tunnels.

  6. Step 6

    6. Beyond the hull breach, climb up to the secured door area. A cyborg assassin guards this egg.

  7. Step 7

    7. Search the upper walkway in the morgue.

  8. Step 8

    8. Look over the railing on the opposite side of the same room, down into the room guarded by ceiling turrets.

  9. Step 9

    9. Go past the missile turret to the egg guarded by a camera and turret.

  10. Step 10

    10. Check the ledge halfway down the ladder on the way to Nacelle B.

  11. Step 11

    11 and 12. Check for both eggs just inside Nacelle B.

  12. Step 12

    13. Follow the Nacelle B tunnels upwards. The egg is beyond a turret in the passage filled with steam.

  13. Step 13

    14. Follow the floor markings towards Pod 2. The egg is on the wall to the left immediately beyond the marked door.

  14. Step 14

    15. Climb across the walkways to the large room. The egg is in its center.

  15. Step 15

    16. Before the door to the next pod, check the left side of the room with upgrade stations.

System Shock 2

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Sources & editorial date

Independently written game guidance. The following sources support quest routes, mechanics and edition notes. Editorial date: 12 November 2026.

In-game names may differ between language versions. Report a correction.

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Game help

How do I treat the four environmental regulators in Hydroponics?System Shock 2 · PC original and 25th Anniversary Remaster

Finish researching Toxin-A once. You can then insert one vial into each of the deck’s four regulators.

  1. Look for the first vials in the office near the elevator and in the room beside the broken replicator. A LabAssistant implant for Research is also there.
  2. Select the toxin in the inventory to begin researching. When prompted in the game, take two units of antimony and one unit of vanadium from the chemical stores.
  3. Drag one researched vial from your inventory to each environmental regulator. Check each regulator label to track which of the four you still need.
Sources

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