Why won't a slot accept my item?

Because it is locked to a different colour. A slot locks to the first colour placed in it and accepts only that colour until it holds four of them, at which point it clears and becomes blank again. A slot that is already full cannot take anything either, but it clears the instant it fills, so you will rarely see one.

Two ways. Usually the belt backs up: it holds seven items, and one more arriving ends the run. The other is a jam — the front item fits nowhere and the HOLD box is occupied by an item that also fits nowhere, so no legal move exists. The end screen says which one happened.

What does the HOLD box do?

It parks exactly one item off the front of the belt so the queue behind it can keep moving. You place it into a slot later, once a slot has cleared. It holds one item only, so it buys time rather than removing the problem.

Does the game get faster?

Yes, but that is not what beats you. Items start arriving every 1.05 seconds and speed up to a floor of 0.16 seconds, which is not reached until 148 seconds. What actually ends runs is the colour count: it starts at three and gains one every 22 seconds up to seven, so from 44 seconds there are more colours than the four slots can hold at once.

How is the score calculated?

One point per item placed, plus a 40-point bonus each time you fill and clear a slot. Clearing slots is where the points are, which is also what keeps the belt moving.

Can I play it on a phone?

Yes. It is designed for portrait play and one-handed use — tap a slot to place the front item and tap HOLD to park it. On a desktop the number keys 1 to 4 select slots and H uses HOLD.

Queue Sort

How to play Queue Sort

Queue Sort is a conveyor-belt sorting game. Coloured items arrive along a belt at the top of the screen, and only the item at the front of the queue — the one with the green outline — can be moved. You send it into one of four sorting slots below. The run ends when the belt backs up completely, so the job is to keep the queue moving.

Tap a slot to place the front item, or press the number keys 1 to 4, which match the numbers printed under each slot. Tap the HOLD box (or press H) to park the front item aside. Press R to start a new run. There is a short cooldown of 0.18 seconds between placements, which is roughly the time an item takes to travel into a slot — you cannot empty the belt in a single burst of taps.

The rule that makes it a puzzle

A slot is not a colour-coded bin. Every slot starts blank and locks to the first colour you put into it. From that moment it accepts only that colour, and it stays locked until it holds four items of that colour, at which point it clears immediately and becomes a blank slot again.

That single rule is the whole game. Four slots that are each locked to a different colour will refuse a fifth colour outright, and the item stuck at the front of the queue blocks everything behind it — including items that would otherwise have somewhere to go. A queue is not a pile: one unplaceable item at the front stalls the entire belt.

The HOLD box is your only relief valve, and it holds exactly one item. You can park an awkward item there to let the queue behind it flow, then place it later once a slot has cleared and freed up. Because it holds only one item, it buys you time rather than solving the problem.

How a run ends

There are two endings, and the game tells you which one you got.

Belt full is the common one. The belt holds seven items, and if another item arrives when it is already full, the run is over. The counter above the belt shows how full it is and turns red at six.

Jammed is the other. If the front item fits in no slot and the HOLD box is occupied by an item that also fits nowhere, you have no legal move at all. Nothing on the board can change without a placement, so the game ends there rather than making you watch the belt fill up.

Difficulty: the colour count, not your reflexes

A run opens with three colours, and one more colour is added every 22 seconds, up to a maximum of seven. This is where the pressure comes from, and it is arithmetic rather than speed.

While there are only three colours and four slots, there is always a slot that can take whatever arrives. At four colours it is exactly one colour per slot, and HOLD is your only slack. From 44 seconds in there are five colours competing for four slots, and from then on a colour with no open slot is not just possible but expected — the only way to survive is to keep finishing slots so blank ones keep coming back.

Items also arrive faster over time, from one every 1.05 seconds down to a floor of 0.16 seconds, but that floor is not reached until 148 seconds and is not what ends most runs. In a balance test of forty runs by an optimal player, every single run ended while five colours were active, at a median of 54 seconds — and at that point items were still arriving only every 0.73 seconds, four times slower than the placement cooldown. The game runs out of room, not time.

Scoring

Each item you place scores 1 point, and clearing a full slot scores a 40-point bonus. Clearing slots is therefore worth far more than placing items, which is another way of saying the score rewards the same behaviour that keeps you alive.

Your best score is saved in your browser on the device where you play. There is no account and no global ranking.

Three strategies that come from the rules

Concentrate, do not spread. Putting one item into each of four blank slots locks all four to different colours and leaves you with no blank slot at all — the worst possible position once a fifth colour exists. Filling one slot toward four is what returns a blank slot to you.

Treat the last blank slot as expensive. A blank slot is the only thing that can accept a colour nothing else on the board will take. Spending your last one on a colour you have only seen once is how a comfortable run turns into a jam two seconds later.

Park, do not panic. If the front item has no home, HOLD it so the items behind it can flow to slots that are open. Just remember it holds one item: park the awkward colour, then spend the next few placements finishing a slot so the parked item gets somewhere to go.

Device support

Queue Sort is built for portrait play on phones and tablets, with every target sized for a thumb, and it also works in a desktop browser using the number keys. It is self-contained, with no download, account, or third-party runtime.

An original game made for QuickWebGames — you will not find it on any other site.