CLOPEN · a free deduction game set on a night shift

Nobody badges out.

Two milligrams of hydromorphone came up short at the count. The cabinet says they were pulled at 21:30. Six people tell you where they were at 21:30. The door readers only record people going in, so one of those stories can't be true. You have to prove which one, with two lines from the logs.

Take shift 1 Play all three shifts

Free, no account, no ads. The demo below runs the game's own code and works on a phone. The full game needs a keyboard.

The CLOPEN desk: eleven statements on the left, each with the room that person claims; two printed reader logs on cream paper; one name highlighted in amber on the Equipment Bay log at 20:50.
Shift 3, two logs printed. (Seed 7, not your ward, so nothing here spoils yours.)

Shift 1: The Short Count

This is the real first shift, running on the game's own code. Tap a door to print its log, and a name to follow that person. Cite two log lines, then file.

Try this: print one log and find two people it can't tell apart. Then spend twelve more minutes on a second door.

The whole rulebook is one sentence

A badge reader records people going in. It never records anyone going out.

That's basically it. Three things fall out of it, and the game is those three things.

  1. A swipe tells you where somebody was at that minute. It tells you nothing about when they left.
  2. A log you've printed is complete. Every entry through that door between 20:00 and 22:00 is on the paper, so a missing name is a fact.
  3. So a story breaks when two lines meet: their last way in to the room they claim, then a swipe through some other door afterwards. If their room's log never brings them back before 21:30, they weren't there.

Here's the wall you hit first. Somebody who badged into the break room at 20:41 and stayed looks exactly like somebody who badged in at 20:41 and slipped out. On that one log, they're the same line.

One log can never prove anything. You always need the second door.

You can't guess your way to a name

Most mysteries ask who did it. CLOPEN asks you to prove it. The report takes a name and exactly two log lines. It only goes through if those two lines, read against that person's own statement, make it impossible.

A name with nothing behind it gets handed straight back, free. A name with the wrong two lines costs ten minutes of the shift, and that person leaves their badge card on your desk: every door their badge touched. The penalty is also evidence.

My favorite part: the code that grades your report is the same code that built the shift. Every ward is generated, and the game throws a ward away unless that same code proves exactly one statement on it impossible, and that it's the guilty person's. The test suite checks four more things on each ward it runs:

  • no pair of anyone else's own lines makes a valid report (it tries every pair)
  • no single log convicts anybody
  • the liar really was in the room they claim, earlier that night, so the lie holds up at first
  • somebody innocent always looks bad

Its test suite runs 2,136 checks over 13 wards of each shift, with every item on that list among them. While building this page I ran 1,000 more wards per shift. All 3,000 generated, each had exactly one impossible statement (the right one), and no single log convicted anybody.

Three shifts, and the doors go dark

Shift Statements Doors No reader Time Par
1 · The Short Count 6 5 1 60 min 3 logs
2 · The Propped Door 8 7 1 72 min 4 logs
3 · Nights 11 9 2 84 min 5 logs

Shift 2 adds somebody who says they were in the med room. That's the door with no reader, so their word is all you'll ever get. They look like the obvious suspect. A story you can't check isn't a guilty one.

Shift 3 is eleven statements and nine doors. Stairwell C has been chocked open for a bed move, so two doors leave no paper at all.

The people who fool you are planted on purpose. One went in early and stayed put past 21:30. Another left the room they claim and came back before 21:30. The second log makes them look terrible. Their own room's log clears them.

Three stars, and an honest clock

Every shift ends on a report card. THE NAME: you closed it. THE CLOCK: you did it in par logs or fewer. And THE CLEAN REPORT means nobody else's name went in the file.

Report card reading REPORT ACCEPTED, three gold stars: The Name, The Clock (4 reader logs printed, par is 4), The Clean Report (nobody else's name went in the file).
A shift 2 report card, from seed 7 (a different ward than yours).

You get enough time to print every log there is. Par isn't. Print everything and the liar gets easy to spot, which is why THE CLOCK only lights at par or under. On shift 1, par is three of the four logs.

Honest gripes

  • Nobody outside my own test runs has played it yet. No reviews, no player count, and no idea how long it takes you.
  • Three shifts is the whole game for now. A different seed gives you a new ward, not a new kind of case.
  • You'll need a keyboard for the rest. On a phone you get shift 1 on this page and that's it, because the title screen, the report and the next-shift button only answer to keys.
  • Wards look alike. Same corridor, same rooms, the same thirteen names shuffled.
  • It's a puzzle set on a ward, not a procedure. Real drug diversion cases run on dispensing-cabinet reports, waste witnesses and people. Door logs alone don't convict anyone.
  • The floor plan is boxes on a corridor. The paper is the good part.

Questions

How long does it take?
I haven't timed real players. Shift 1 is six people and two logs can close it. It's the shortest of the three, and it's the one on this page. The clock only moves when you print a log or file a wrong report, so take all night.
Is it really free?
Yes. No account, no ads. Your stars save in this browser.
Does the demo count?
Yes. File an accepted report on shift 1 here, and the full game opens on shift 2 in this browser.
Can I play on my phone?
Shift 1 above, yes. Shifts 2 and 3 need a keyboard.
Is it like Obra Dinn or Golden Idol?
Same itch: you prove the answer instead of picking it. Much smaller. One rule, two lines, three shifts.
I work nights on a unit. Is this about us?
It borrows the details: the narcotics count, the propped med room door, the clopen. Who did it is random. The game draws from thirteen names (nurses, CNAs, a clerk, a pharmacy tech, transport, respiratory), and everyone else on the shift told the truth. Name the wrong one and it costs you. It's a puzzle set on a ward, not a procedure. In real life, door logs alone don't convict anyone.
What's a clopen?
Closing a shift at night and opening the next one in the morning. It's also the math word for a set that's closed and open at once, which is every time window in this game until you print the second log.
Can I get a different ward?
Add ?seed= and any whole number above zero to the game's address. The solver proves every ward before it deals one.

The count is still short.

Shift 1 is up there, on the real engine. If you've filed it already, shift 2 is waiting.

Play CLOPEN Take shift 1

P.S. If you got REPORT ACCEPTED in the demo, the full game already knows. It opens on shift 2, The Propped Door, where somebody swears they were in the one room you can never check.