Shift At Midnight has two halves that get in each other's way. One is a shop that needs restocking, deliveries and a nightly quota. The other is a screening job where getting it wrong summons something at the end of the night. This reference covers both, plus the threats and modes that sit behind them.
Where the game is decided. Pack the customer's items, scan their ID against the database, question them about the identity they are presenting, then either complete the sale or act on the conclusion that they are not human.
Sources: In-game
Restocking shelves, receiving deliveries, cleaning, and meeting a nightly quota. Individually trivial, collectively the reason you are tempted to rush a screening — which is exactly what they are there for.
Sources: Steam store description
Creatures that impersonate specific named people already present in the customer database. Nine customers are confirmed to have impostor versions. A doppelganger that gets through leaves quietly and escalates the night rather than attacking on the spot.
Sources: In-game database
A spider-like being of abnormal size that arrives at the store at the end of a shift, summoned by a doppelganger you failed to catch. It is the delayed consequence of a bad call at the counter, not a random event.
Sources: In-game
Judged impostors can be shot at the counter. A body shot sends them running and needs a follow-up; a headshot ends it immediately. What is left behind has to be cleaned up, which costs shift time you also owe the quota.
Sources: In-game
When the night turns against you, the game shifts from retail to survival — boarding up doors, setting traps and hiding rather than fighting.
Sources: Steam store description
The main campaign, running a fixed sequence of nights. Completing it unlocks the second mode.
Sources: In-game
Unlocked by finishing Story Mode. Unlimited nights with no completion condition — it ends when all players die.
Sources: In-game
Most of what is written about Shift At Midnight describes it as a horror game with a shop attached. It is more accurate to say the shop is the horror mechanic, because the shop is what stops you from doing the screening properly.
Nothing in the shop is hard. Shelves need refilling, deliveries need putting away, the floor needs cleaning, and a quota needs hitting before the night ends. Any one of those is a chore.
The screening is not hard either, taken alone. Scan an ID, look at the photo, look at the person, ask some questions about who they claim to be.
The game is the two at once. Every minute spent being careful at the register is a minute the shelves are empty and the quota is slipping, and every minute spent restocking is a customer processed faster than they should have been. There is no setting where you can do both properly, and that is not a balance problem — it is the entire design.
The consequence structure is what separates this from most co-op horror.
Waving through a doppelganger produces no feedback. The transaction completes, the customer leaves, the shift continues. What actually happened is that it went and alerted the Entity, and the Entity comes at the end of the shift.
So the information you need to correct your behaviour arrives after the point where correcting it is possible. You cannot learn from the mistake within the run that contains it — only across runs, which is why knowing the confirmed impostor roster in advance is worth more here than reflexes.
Story Mode is the campaign and runs a fixed number of nights. Endless Mode unlocks when you finish it and removes the ending entirely — nights continue until every player is dead.
The distinction matters for how you play. In Story Mode a bad night is a setback inside a structure that will end. In Endless Mode there is no structure to outlast, so the screening discipline is the only thing keeping the run alive.
You run a gas station on the night shift, alone or with up to two other players. The shop side means restocking shelves, handling deliveries, cleaning and hitting a sales quota. The other side means screening every customer at the register with an ID scan and questioning, because some are doppelgangers.
Scan the customer's card at the register, then compare the photo held in the database against the person standing in front of you. Because doppelgangers impersonate real people whose details are genuinely on file, the identity itself checks out — the discrepancy is between the filed portrait and the body.
You have a firearm at the counter for executing customers you judge to be doppelgangers. A body shot wounds and the target runs, so it takes a follow-up; a headshot kills outright.
Two. Story Mode is the main campaign over a fixed run of nights, and Endless Mode unlocks after you finish it — unlimited nights that end only when every player is dead.
Every shift is randomly generated, so the customer lineup, which of them are impostors and the order they arrive in change each run. Endless Mode exists specifically to keep that loop going after the campaign is done.