Security 51 does not give every player the same queue of visitors. A useful walkthrough therefore cannot tell you to approve “the third person” or copy one run’s earnings. It has to preserve what is stable: the bulletin for each day, the tool that can prove its exception, the correct response button, and the extra city or Isolation Ward job that must be handled before the shift closes. This route follows those stable checkpoints from Day 1 through the moment Day 30 unlocks the Branching Timeline.
Release boundary: Security 51 launched on Steam on August 12, 2026. This article was checked against the launch store data, Alawar’s launch announcement, and post-launch walkthrough captures dated or updated August 12. No later official patch was present in the captured Steam news feed. Visitor order is randomized, so the current bulletin and live feedback outrank any example visitor, payout, or purchase sequence below.
Turn the bulletin into three verdict columns
Before pressing Start Shift, rewrite the day in decision order. The June demo update added this pause specifically so instructions can be reviewed without burning shift time, and the full release retains that desk flow.
- Forced entry: copy every condition printed under the instruction that says to let someone through while ignoring all other instructions. If one is proven, use the green outcome even when a lower-priority defect is also present.
- Security call: copy the conditions assigned to the security button. Do not substitute a red denial; the game treats those outcomes differently.
- Baseline denial: list the mismatches or anomalies covered by the ordinary “let through except” rule. These produce a denial only after neither override applies.
Keep the wording on the live manual visible if two conditions collide. The tables below summarize the verified launch route, but they are not a replacement for a changed bulletin. A correct diagnosis with the wrong response button is still a mistake.
The growing toolset is easier to remember as an unlock ladder:
| First important day | New check | Question it answers |
|---|---|---|
| Day 2 | X-ray/body scanner | Is an external body region abnormal? |
| Day 4 | Polaroid | Does the developed image reveal a photo anomaly? |
| Day 7 | Organ MRI | Is a named organ or internal region abnormal? |
| Day 9 | Thermal scanner | Is the target area unusually hot or cold? |
| Day 11 | Bone MRI | Is the skeleton, or one named bone region, abnormal? |
| Day 15 | UV light | Do the documents contain a hidden symbol or trace? |
| Day 21 | Blood sampling and microscope | Which named organism or blood anomaly is present? |
| Day 25 | Rorschach test | Does the answer contain the day’s trigger category? |
| Day 29 | Blood-type test | Does the sample match the protected blood type? |
Days 1–6: separate denial, security, and elevator containment
The first six days are not merely a tutorial block. They teach three different desk outcomes, then turn the returning elevator into a second checkpoint. Do not build the habit of pressing Denied for every bad result.
| Day | Stable rule and tool | Action that prevents the common mistake |
|---|---|---|
| 1 | Compare the two IDs for name, number, and face; stamp Approved only when all three agree. | After four approved visitors fill the elevator, send it down. Treat the end report and shop as part of the tutorial, not as proof that later queues will have the same size. |
| 2 | Deny a document mismatch or external body anomaly. The X-ray tutorial supplies the body check. | Run the scanner before deciding that clean paperwork is enough. Watch the clock, but learn the complete inspection before chasing the time bonus. |
| 3 | A fake name or an anomaly on the neck requires Call Security; other listed document conflicts remain ordinary denials. | Read both the defect and the requested response. A red stamp on a security-call case is not a safe substitute. |
| 4 | A Polaroid anomaly requires security. | Move the camera toward the strongest static, wait for development, then judge the image. An undeveloped frame is not evidence. |
| 5 | Ordinary mismatches and external anomalies are denied; a forged medical certificate escalates to security. | Ask for the certificate after finding the body issue. An authentic certificate does not erase the day’s body-denial rule, while a forged one changes the response. |
| 6 | External body anomalies call security, but a photo anomaly is the explicit forced-entry condition. | After the elevator returns, open its camera and inspect riders with the available modes. Isolate any fungus cases the camera exposes, enter the Ward, and complete the introduced research rather than ending immediately. |
Day 6 is the first day where a good desk record can still fail below the counter. The outbound check decides who descends; the returning camera decides who is safe to release. Keep a headcount, change camera modes when the normal view is inconclusive, click the abnormal rider, and then choose the action named by the current protocol. The walkthrough run used Night Vision and Thermal Imaging to expose fungus, but the hub warns that visitor rolls vary.
Days 7–14: schedule the city and Ward before the last visitor
Level 1’s second half adds two off-desk obligations. Citywide Field Operations spend Sanity and help contain the active outbreak; successful Ward research can unlock later operations. The safe rhythm is: read the bulletin, choose the day’s Field Operation, note whether the Ward is available, run the visitor queue, inspect the returning elevator, then verify that no required off-desk action remains.
| Day | Desk verdict | Off-desk checkpoint |
|---|---|---|
| 7 | Use the new Organ MRI; an internal-organ anomaly calls security. | Open the City interface and perform the introduced Field Operation. The Ward is unavailable in the recorded route, so do not wait for a research option that is not there. |
| 8 | Deny mismatched documents or internal-organ anomalies. | The reference run paired Collect Samples with Arithmometric Test. Continue checking the returning elevator because isolated subjects feed the research layer. |
| 9 | Hypothermic areas call security; hyperthermic areas force entry. | Use the Thermal Scanner deliberately: the recorded route renders heat as pink and cold zones as black. Its Ward choice was Prolonged Inhalation of Lilac 8. |
| 10 | A heart anomaly calls security; a Phantom Hound in the developed photo forces entry. | Search the strongest Polaroid static for the Handbook image. The recorded city action was Outreach, with no Ward research available. |
| 11 | Document mismatches or bone anomalies are denials. | Use Bone MRI and inspect any requested medical certificate; a forgery escalates to security. The reference research was Dihydrogen Monoxide Treatment. |
| 12 | A rib anomaly calls security. | Scan the named skeletal area rather than condemning every unusual bone result. The route used Study Los Huevos Influence and Quartz-12 Exposure. |
| 13 | A brain anomaly is the forced-entry condition. | Use Organ MRI only as far as the bulletin requires. The recorded pair was Prevent Mass Gatherings and High Temperature Exposure. |
| 14 | Bone anomalies call security. | Confirm the security button, not Denied, after a positive bone result. The route closed Level 1 with Local Los Huevos Propagation and Retro-Acoustic Test. |
The fixed operation names in one writer’s route are less portable than their order. Research results unlock operation choices, and a different earlier result can change what appears. Select the operation that addresses the live city threat, and record what it unlocks. If the Ward is scripted closed, accept the closure; if it is open, do not throw away the day’s research opportunity by ending the shift too early.
Days 15–20: use UV and exception scans only when they can change the verdict
Promotion to Level 2 raises the penalty for careless decisions and introduces hidden marks. The efficient inspection is not “use every machine on everyone.” Begin with documents and the shortest relevant visual test, then open the deeper scanner only if its result can trigger security or a forced entry.
| Day | Call security when | Let through despite lower rules when | Best inspection order |
|---|---|---|---|
| 15 | Organs are rotting, or a skull appears under UV. | Mysellium appears on the papers under UV. | Documents → UV → Organ MRI. The recorded pair was Gathering Zombification-Case Data and Quartz-12 Exposure. |
| 16 | Chitinous skin growths are present. | The photo contains microchip fragments. | Body scan → Polaroid on a positive case. The route chose Deploying Containment Units and Prolonged Inhalation of Lilac 8. |
| 17 | No separate security trigger is listed in the captured route. | “Other traces” appear under UV. | Documents → UV → Bone MRI. The reference pair was Deploying Crowd-Control Units and Quartz-12 Exposure. |
| 18 | The lung or liver is packaged. | No forced-entry exception is listed. | Scan only the named organs. The route used Gathering Zombification-Case Data and High Temperature Exposure. |
| 19 | Gray mold is visible on the skin. | A hypothermic area is present. | Body scan → Thermal Scanner. The route selected Barricading and Setting Traps; the Ward was closed, so no research was possible. |
| 20 | No security condition is listed. | Yellow resin appears on the bones. | Use Bone MRI only when resin can reverse a denial. No Field Operation was listed; the Ward choice was Retro-Acoustic Test. |
Day 15 establishes the core Level 2 pattern: an ordinary defect may be superseded by a hidden paper mark. Day 16 moves that exception into a photograph; Day 19 moves it into temperature; Day 20 moves it into the skeleton. When your decision is marked wrong even though you spotted the obvious anomaly, audit the exception tool before blaming the scanner.
Days 21–24: protect time for the microscope
Blood Sample Analysis is slower than the earlier scans because it has a collection step, a microscope examination, and a printed or confirmed result. On a blood day, remove every unnecessary test from the queue. Take the sample carefully, identify the named result, and do not act on a half-read slide.
| Day | Blood or supporting rule | How to keep the shift under control |
|---|---|---|
| 21 | Erythrocytus Necroticus calls security; Macrophagus Pakumanii forces entry. | Keep the names in separate verdict columns. The reference path used Setting Up Fortified Positions and Low Temperature Exposure. |
| 22 | A UV skull calls security; a Carrion Fly in the Polaroid image forces entry. | Use UV first, then develop the exception photo before committing. The route paired Distributing Corpse-Eater Cocoon with Quartz-12 Exposure. |
| 23 | Document mismatch or internal-organ anomaly is denied; blue electrical tape on the organs forces entry. | Inspect the abnormal region for the exception. The recorded pair was Deploying Containment Units and Dihydrogen Monoxide Treatment. |
| 24 | Larva Locustarum in the blood is the forced-entry condition. | Fully confirm the slide before choosing. The reference run used Testing Anti-Zombification Microchips; do not copy its payout as a target. |
If Day 21 or 24 times out, the useful diagnosis is not “work faster” in the abstract. Count how often you opened a scanner that could not affect that day’s decision, how long documents stayed spread across the desk, and whether you left City or Ward work until after the final visitor. Printing and scanning-speed upgrades become more valuable here because they shorten a named bottleneck; food and Sanity supplies still take priority if either survival meter is close to ending the run.
Days 25–30: read answer categories before opening another scanner
Level 3 adds the Rorschach test, then a blood-type check. These are category tests: the response does not need to repeat a single fixed sentence, but it must contain the object or color named by the day’s bulletin. Keep those categories beside the manual and apply them before an ordinary denial.
| Day | Security trigger | Forced-entry trigger | Route note |
|---|---|---|---|
| 25 | The Rorschach answer mentions red. | None listed. | Documents → Rorschach. The reference pair was Collecting Data on BSODeaD and DUCC Project Display. |
| 26 | The answer names a vehicle or flowers. | The answer names a cat. | Classify the answer first. The route used Mapping the Probabilities of Crushing BSODeaD and Energy Sphere Experiment. |
| 27 | No separate security condition is listed. | Runic symbols under UV or a hypothermic area. | A mismatch can still be overridden by UV or Thermal proof. The recorded Ward research was Prolonged Inhalation of Lilac 8. |
| 28 | Advanced Tarrification of the Liver. | Continuum Rupture on the skin, or stones in the Rorschach answer. | The route chose Initiating Convergence Points 0-1-Crown-Sea and High Temperature Exposure. Preserve a screenshot if its reported liver/skin feedback bug appears. |
| 29 | Examen Viride, Erythrocytus Fragmentatus, or microchip fragments in the photo. | Blood type AB+. | Reserve time for sample analysis and a Polaroid check. The reference research was Dihydrogen Monoxide Treatment. |
| 30 | Advanced Chipization of the skin. | Blood type AB−, or an animal in the Rorschach answer. | The route finished with Stabilizing the Sustained Nexus 1-0-Emperor-Gold and Quartz-12 Exposure. |
Day 28 is the one point where the recorded walkthrough itself flags inconsistent feedback. That report is evidence of a possible launch-build problem, not proof of a universal rule. Capture the bulletin, visitor result, and penalty screen; update the game and compare the newest official notes before changing your route around it.
Diagnose the layer that produced the penalty
A wrong result is useful only if you identify which layer failed. Do not change the shop plan, tool order, and verdict logic together after one penalty; that erases the evidence needed to fix the next attempt.
| Failure signal | Likely failed layer | Next controlled check |
|---|---|---|
| You found the named anomaly but still lost money | Response priority or wrong button | Return to the live bulletin and ask whether the condition belongs to forced entry, Call Security, or ordinary denial. Keep the same scan result and change only the response. |
| The shift times out after blood tests unlock | Tool selection and desk handling | Mark which tests can change today’s verdict before starting. On the retry, remove one irrelevant scan from every visitor and place completed documents in the same location. |
| The desk report is clean but the day still deteriorates | Elevator, City, or Ward work | Reconcile the returning elevator, then check whether one Field Operation and the available research were completed. A good front-desk score does not close those systems automatically. |
| The reference operation is missing from your City menu | Earlier research state or scripted availability | Do not click a vaguely similar option. Read the current threat, record the available choices, and use the option unlocked by your own research history. |
| Sanity collapses during an otherwise accurate route | Resource timing | Check the meter before committing to a Sanity-consuming operation. Protect the next shift’s survival purchase before buying a convenience upgrade. |
| The named visitor or queue position never appears | Randomized visitor roll | Ignore the reference person and apply the day’s rule to whoever arrives. The bulletin is portable; queue position is not. |
| Day 28 feedback contradicts the visible bulletin | Possible launch-build discrepancy | Preserve screenshots of the rule, liver/skin results, chosen button, and penalty. Compare a current official patch before turning one report into a new rule. |
Use the end-of-day report as a narrow test result. One document error calls for a slower name/number/photo pass, not a new food budget. One missed Rorschach override calls for a category note beside the manual, not a full scan of every organ. A returning-elevator failure calls for a camera checkpoint, not faster stamping. When each retry changes one layer, the next report tells you whether the correction worked.
This also protects the route from updates. If a patch changes one bulletin, tool label, or operation unlock, replace that row with the live result while keeping the rest of the diagnosis intact. The current client should win locally without forcing you to discard a verified thirty-day progression map.
Stop at the Branching Timeline instead of inventing its solution
After Day 30, the verified route reaches a cutscene in a futuristic area and then returns to the Shift Map with a tutorial for manipulating alternate outcomes. The stated objective is to identify the BSODeaD hacker group by testing timelines. The supplied walkthrough ends at that unlock. It does not prove a winning branch sequence, every ending, or a full-game day count.
That boundary matters because the supplied unofficial wiki pages are not reliable substitutes. They claim 69 achievements while the live Steam page lists 68, and they turn hidden achievement names into precise ending explanations that Steam does not publish. Another supplied site labels its own walkthrough as pre-release/demo-verified and explicitly avoids day-by-day full-release claims. Use neither to fill the missing Branching Timeline route.
At the unlock, protect a save if the client permits it, record the state of the Shift Map before moving any branch, and treat each experiment as a controlled comparison. Continue only from visible in-game consequences or a later reproducible post-launch route. The reliable promise of this walkthrough is Day 1 through Day 30: daily verdicts, tool order, City/Ward checks, and the exact point where verified instructions stop.
Official game and launch notice
Security 51 on Steam · Security 51 at Alawar · Official launch announcement