Get permission to enter Yuri’s simulation
Find Yuri Scarlet in the lobby. Current community documentation describes an Officer rank requirement and a set of prerequisite badges highlighted in Manhattan's codex. Accepting Yuri's challenge awards INITIATION and opens access to the simulation.
Check the highlighted badges in game. The official EXOTIC-EXONERATION description asks for all badges except FULL-HOUSE, OVEREQUIPPED and LAST-RITES-OF-A-RUINED-KING. That wording is broad; use Yuri's dialogue and the codex to resolve the actual prerequisite set, especially for removed or event badges. Our badge index lists every badge on the official list, plus the retired ones.
Update, September 18: the developer removed SOLE_PRACTITIONER from Yuri's requirements, and that badge's own description now marks it optional. The EXOTIC-EXONERATION text predates the change. The developer adds that its progress can be tracked at spawn in a private or restricted server.
Once accepted, go to Yuri's room next to the showers. The current community quest guide puts the simulation teleporter on a seat there; older versions placed it above an M1911 Regalia display. Either way, it is not the black cross that leads to the Tunnels.
Pick a difficulty, then a class
The simulation opens with three difficulties: Easy, Normal and Insane. Only Normal and Insane pay out. Miraheze's quest guide says an Easy completion grants no rewards, and JST's walkthrough says the same: to get Night Stalker or Regalia, finish on Normal or Insane. Easy's longer timer still makes it a way to learn the layout.
Difficulty sets the timer, how often enemies spawn enraged and whether two extra limiters appear. Enemies also get more HP and respawn faster on the higher settings. Only Insane runs make the lobby leaderboard.
You start outside the plant with an MX-21 torch. Finish Yuri's entrance dialogue to lift the lobby barrier, then choose a class: Operator, Pointman, Corpsman and Leader are at class selection, and Classless is in a small room nearby. Every class loses its TRC-44 radio, and each is tuned for the challenge:
| Class | In the simulation |
|---|---|
| Operator | 10% faster movement. |
| Pointman | Maximum HP cut to 105. |
| Corpsman | Regenerates 1 HP per second and can’t be stunned. The MPR-VII replaces the primary, and the VIREL-M MedTac heals more over 45 seconds, with about a minute of cooldown. |
| Leader | Bash recharges faster and reaches further. |
| Classless | Lock-17 (F), MX-21 torch and night vision. |
Then pick one of four spawns: Adam Dice's room, Sector 1, the Sector 2 entrance or Sector 2 Main Hall. The equipment table offers the Gilbert Plush if you own its gamepass and the Night Stalker once you have unlocked it. Anything you take from it before choosing a class is removed when you choose, so walk back and equip it again.
What’s different from a normal run
- A smaller map. Reactor 4, most of Sector 3 and some Sector 1 hallways are gone, along with the doors and most props. Adminstal lockers have moved, and ammo boxes are scattered around.
- Ammo boxes are safe spots. Enemies ignore you while you use one, and you stay immune to damage for about two seconds after.
- No infection, more stamina. You can't become infected, and stamina lasts about 28 seconds.
- Guns to pick up. An AK-74 with 90 reserve rounds waits at the Sector 2 chokepoint behind a gate, where a Riser and two Furies are locked in. An SHC-23 sits near a box in what remains of Sector 3. JST picks up and equips a Shielder’s Beanbag Shotgun during his October 17 classless walkthrough, around 3:30–3:50. Miraheze removed its pickup and drop-rate claims on October 27. The older footage does not establish current availability; plan your run without this optional pickup.
- Axes hit one enemy per swing. That includes their reskins.
JST's September 19, 2026 Pointman walkthrough was recorded on Normal the day after the rework and shows the full run. We sampled it every 20 seconds to check the kill counter, timer and boss order. It is supplemental footage, not an independent playtest by this site.
Keep the timer alive
A countdown runs for the whole kill phase; if it reaches zero, the attempt fails. Kills, combos and pickups add time, and the clock pauses during execution animations. It stops for good once you reach the kill target.
| Difficulty | Starting time | Added per kill |
|---|---|---|
| Easy | 8:00 | 10 seconds |
| Normal | 3:30 | 4 seconds |
| Insane | 2:00 | 3 seconds |
Killing several enemies in quick succession builds a combo, up to 8x, worth as much as 3 extra seconds per kill. Go too long without a kill and the combo resets; an execution doesn't break it.
Pickups
Four kinds of pickup appear at random around the map:
- Time
- Adds 20 seconds to the timer.
- Heal
- Restores 25 HP.
- Forcefield
- Makes you immune to damage for 7 seconds.
- Ammo
- Gives your firearms an endless magazine for 15 seconds.
The developer raised the time pickup from 15 to 20 seconds on September 20. Chasing pickups across the map is a trade-off: JST tries it in his video and warns that you'll probably get lost and surrounded.
Work through the kill milestones
The objective is 200 infected kills in one life. Death, leaving or disconnecting wipes the attempt; there are no checkpoints. Ordinary infected stop respawning at 200 kills. While a milestone boss is alive you can't finish the objective, even with 200 on the counter, so deal with it first. Bosses that spawn far away walk toward you, and they're sometimes highlighted through walls.
| Kills | Boss | Notes |
|---|---|---|
| 50 | Mikhail | Yuri offers a kill reset for +100 maximum HP first. In the simulation Mikhail has 2,000 HP and no regeneration. |
| 75 | Classless Viral | — |
| 100 | Classless Executioner | — |
| 125 | Dave | Skipped on a classless run. 1,500 HP, no regeneration, and a 5.5-second stun after his rage ends. |
| 175 | Viral Leader | — |
| 200 | D-Zero | Yuri calls you back to the lobby; the checkpoint leads to the final arena. |
Yuri’s offer at 50 kills
Before Mikhail, Yuri offers +100 maximum HP in exchange for resetting your kills to zero. Accepting also resets the limiters; declining continues the run and brings on Mikhail. Decide whether the extra health is worth repeating the opening kills against the clock.
Limiters and difficulty
Limiters make each stretch harder than the last, adding or strengthening an effect every 25 kills. The current community guide no longer publishes a full threshold table; this is what it lists:
- Enraged respawns are on from the start. Lurkers, Shielders and Slashers can spawn enraged: 5% of the time on Easy, 30% on Normal and 75% on Insane. Enraged Lurkers have double HP and run much faster but deal only 10 damage.
- Slower reloads, which also blunt Adminstal's Haste vial.
- A longer bash cooldown.
- Unstable zones from 125 kills. Stay in one zone for 45 seconds and you take 2 damage per second until you leave; a new unstable zone lands on you every 3 to 5 minutes.
- Paranoia, Insane only, from 50 kills. Every few minutes you are teleported somewhere random, usually away from enemies.
- Control inversion, Insane only, from 100 kills. Every 60 to 120 seconds your movement inverts for 5 seconds. Miraheze says it ends after the first objective is fully complete. Reaching 200 kills alone does not complete that objective while a milestone boss remains alive; this boundary has not been tested in game by this site.
Up to 29 infected can be alive at once: 9 Lurkers, 4 Risers, 6 Shielders, 5 Slashers and 5 Furies, all from fixed spawns. A warning sign hovers over a spawn point when an enemy is about to appear near you. Shielders no longer rush, and Furies have lost their stagger immunity.
Reload with space around you and know your way out of an area before it turns unstable. JST keeps returning to one main position so he isn't surrounded, and falls back toward Gate 1 when Dave charges.
Force D-Zero to retreat
At 200 kills, follow Yuri's call back to the lobby and go through the checkpoint into the final arena. Your bash cooldown rises to 60 seconds there. The community mechanics describe a six-backstab victory, rather than depleting a normal boss health bar.
- Read the teleport warning. “FALL BACK” signals a position in front of you; “BEHIND YOU” signals a position behind. Do not walk into him while he is stationary after a teleport.
- Pass the quick-time event. His rush or rage displays key prompts. Follow the keys shown on your platform rather than anticipating one fixed input.
- Watch the bash meter. A successful stun fills it by 50%. When it is ready, get behind the stunned D-Zero and bash.
- Clear the summoned enemies. The mechanics page describes three Cultists appearing after each backstab. Make space before the next attack cycle.
- Repeat until he retreats. Complete the closing Yuri dialogue and wait for the badge award before leaving.
The final encounter and the Tunnels use different D-Zero mechanics. A stun-and-run escape tactic from Tunnels does not complete Yuri's arena.
Standard Night Stalker versus Regalia
- EXOTIC-EXONERATION
- The official badge permanently unlocks Night Stalker after returning from Yuri's simulation with clean data.
- LAST-RITES-OF-A-RUINED-KING
- The official reward is the Night Stalker Regalia Special Edition. Current community quest documentation links this award to completing the simulation classless.
Both need a Normal or Insane completion; Easy grants neither. A classless Underequipped run in the main facility does not award Regalia either. It is a separate challenge with a different finish condition. HEART-OF-MENLO is an official developer-event badge, not the named reward for this simulation.
Does Private Server Extras unlock Night Stalker?
Miraheze’s November 2 revision says PS Extra commands can give the pistol without unlocking it for normal use. For a permanent ordinary unlock, complete Yuri’s simulation and earn the badge. The official pass description also says using commands disables badge awards for everyone in that server; owning the pass alone is not stated to do so.
If the simulation is still locked
Check your rank, the codex's marked requirements and whether you accepted the request from Yuri. Do not treat a general badge total as sufficient. If an attempt ends unexpectedly, keep any recording of the issue; this guide cannot determine eligibility for a manual award.
Seasons, score and the leaderboard
The developer’s September 20 patch split the simulation leaderboard into monthly seasons. A new season starts at 00:00 UTC on the first day of every month and wipes the leaderboard. The first reset under this system is October 1, 2026.
- REGALIA'S CONQUEROR. The top 3 players of the current season get this in-game title above their head. It is lost if you drop out of the top 3 or when the season resets, unlike EXOTIC-EXONERATION and LAST-RITES-OF-A-RUINED-KING, which are permanent unlocks.
- Insane runs only. Miraheze's quest guide says the lobby leaderboard lists Insane completions.
- Score, not time. A live points counter sits below your UID in the top right. Kills, executions and pickups earn points, and the end screen shows small red point totals beside each stat.
- Top 30. The leaderboard now lists 30 places instead of 10, with each run’s time and your Roblox name.
- RUN COMPLETE. Finishing the dialogue after D-Zero and Yuri’s ending now shows your stats and score.
Other changes in the same patch
Ordinary infected stop respawning at 200 kills, rather than when the final boss spawns, and bosses that spawn far away now move toward you until you are in their detection range. The developer expects zero or only minor balance changes to the challenge from here. A September 24 follow-up added four custom soundtracks and fixed the music slider and the M settings keybind.
Sources & verification
First checked September 23, 2026; rewritten September 27 for the reworked challenge. Official sources establish the rewards, published badge requirements and season rules; the simulation mechanics come from the current community quest page, retrieved directly, and match the developer's patch notes and JST's footage where they overlap. The October 28 check distinguishes JST’s older Beanbag pickup footage from Miraheze’s later removal of that claim; current availability is unverified. Night Stalker command access was rechecked November 3; the Control Inversion ending condition was rechecked November 4 against Miraheze revision 7761. No independent in-game run was performed.
- Miraheze: Night Stalker, revision 7744 (November 2 UTC; read November 3) — command access does not grant a normal unlock; official PS EXTRAS pass — server-wide badge restriction when commands are used.
- Roblox: EXOTIC-EXONERATION and LAST-RITES-OF-A-RUINED-KING.
- Roblox: SOLE_PRACTITIONER — marked optional since its September 18 update.
- Examination official Discord, #updates — developer patch notes of September 18 (timer display, SOLE_PRACTITIONER), September 20 (seasons, scoring, pickups, respawns and boss pathing) and September 24 (soundtracks).
- Miraheze: Blood Handed Retriever, revision 7761 (November 3 UTC; read November 4, 2026) — entry, difficulties, timer, pickups, classes, bosses, limiters and enemies. The November 3 edit changes Control Inversion's end from 200 kills to full completion of the first objective, and completes the previously unfinished Paranoia sentence. The earlier October 27 edit removed the Classless Beanbag pickup and 35% drop-rate claims; it does not establish a gameplay change.
- Miraheze: D-Zero, simulation mechanics — QTEs, meter and backstab victory (last edited September 17).
- JST: Updated Night Stalker guide — September 19 Pointman run on Normal. Frames sampled every 20 seconds show the 200-kill counter, the timer and combos, Dave at 125 and the Viral Leader at 175 kills, and a RUN COMPLETE screen; the author's captions say only Normal and Insane grant rewards.
- JST: Night Stalker & Regalia guide — October 17, 2026 classless run on Normal. We sampled the footage throughout and checked the Beanbag Shotgun pickup sequence around 3:30–3:50 more closely; the footage documents that older run, not current availability, a drop rate or a new patch.