Sweepmark: one operator, one compound, and a shot you can prove before you take it

01  What Sweepmark is

Sweepmark is a free browser tactics game about one operator clearing one compound. You drop in at a breach point on a thirteen-by-eleven grid held by five hostiles, and you get out again by neutralising all of them before they put three rounds into you. It runs in a single tab, needs no account, and installs nothing.

It belongs to a specific lineage: the simultaneous-turn tactics game — you commit a plan, the enemy commits one you cannot see, and both play out at once. The games that made that idea famous, Frozen Synapse and Door Kickers, are paid and native and start with a campaign. Sweepmark takes the combat slice alone and puts it in a browser tab: a mission is a few minutes, and a clean clear is often under ten rounds. It is not a shooter in the reflex sense — you are never timed, and never killed by something you could not have seen coming.

02  A round is one move and one shot — and both sides commit blind

Every round has three beats. Move: drag your operator to a highlighted tile, or tap one within reach, and a dashed line shows the route. Aim: tap any tile to cover it with your shot. Execute: press the button, and both sides carry out their plans at the same time in a short replay.

The budgets are tight and worth knowing exactly. Your operator covers up to four tiles a round; a hostile covers two. Your weapon reaches eight tiles, theirs reaches six. You have three health, and every hostile dies to a single hit — so the asymmetry cuts both ways.

What makes it a tactics game rather than a puzzle is that the hostiles plan without seeing your order. They react only to the last place they observed you, so the plan you just committed is hidden from them. Both plans then resolve together over forty-eight sub-steps the replay renders as about three seconds: what you watch is two intentions colliding, not a turn you took and a turn they took. Holding position and holding fire are real orders — a round spent repositioning behind cover, taking no shot at all, is often the round that wins the mission. It just costs you rank.

03  The rules are geometry, so you can prove a shot before you take it

Whether a shot lands is decided entirely by two things: is the target within reach, and is the straight line between the two tiles clear. Walls block it. Cover blocks it. Doors block it. There is no accuracy roll, no damage variance and no critical hit.

Your operator auto-aims at whatever tile you tap, so its firing arc is generous — a forty-five degree half-angle around the line to the target. A hostile instead holds a fixed arc of about thirty-five degrees, which is why flanking works and why coming at an arc from behind is so much cheaper than trading shots.

The interface tells you the answer in advance. The aim line turns green when the shot will connect and red when it will not, and that preview is computed by the same function the resolver uses, so it cannot contradict what actually happens. A red shot is not a low-percentage shot; it is a genuine miss. The tracer still fires so the tap has feedback, but it cannot neutralise anything — and the game will not let a red line quietly kill someone who wandered onto the target tile.

When a shot does miss, the game says why: out of range, a wall in the way, or the target moved off your line.

04  Reading the board: the red wash and the four-tick window

Before you commit anything, the board paints a flat red wash over every tile currently inside a hostile’s arc with a clear line to it. Overlapping arcs collapse into one edged zone, so the danger area reads as a single shape you can plan around — but it is a snapshot, not a guarantee, and knowing the difference is most of the learning curve. A hostile that has already spotted you advances up to two tiles toward where it saw you, and its arc moves with it. Red is where you are covered now, not where you will be covered in two seconds, and a clean tile can be swept up mid-round by a hostile walking a sighting. So end your move outside every arc, and break the line of sight that put you in one.

A subtler rule the board does not advertise: a hostile cannot fire the instant it sees you. It needs the opening beat of the round to acquire, and only shoots from sub-step four of the forty-eight. A move that clips a cone edge at the start of the round and leaves it is survivable; one that ends inside a cone is not, however brief. That rewards decisive routes — a fast four-tile crossing often beats a timid one-tile step, because it is out of the arc before the shot exists.

Doors are the most underused tiles on the board. They are walkable and they block sight permanently — nothing opens them, and nothing passes through and turns them transparent — so a doorway is a sight-break you can stand in: an operator in a doorway can shoot out and cannot be shot back through it. Cover is the weaker cousin: it blocks lines passing between two other tiles but not lines ending on it. Hide behind cover, not on it.

05  The hostiles plan blind, and that is the whole game

Until a hostile has observed you — you inside its arc, with a clear line — it holds its post and covers its spawn direction, drifting at most a tile so a stalemate still breathes. Once it has observed you, it advances up to two tiles toward where it last saw you and turns to face that spot.

It does not know about the move you just committed. Break sight and move, and it walks to where you were and covers an empty square while you are already somewhere else. That rule is the engine of the game: you are not out-shooting hostiles, you are feeding them stale sightings and arriving from a direction their arc is no longer pointing at. It is also why their two-tile budget matters so little and yours matters so much. None of it is random — hostile planning is a pure function of the state, with a seeded generator used only to break ties.

06  Four compounds, three conditions for an S, and one number worth keeping

Sweepmark deals one of four compounds, each thirteen by eleven with five hostiles and its own par: The Atrium at par four, The Annex at par five, The Depot at par four, and The Vault at par five. The Vault plays differently — a central spine wall splits it in two and only three crossings get you across, so you commit to a side and the order you sweep in matters more there than anywhere else.

Clearing a compound always earns at least a C. The S-rank is locked to three conditions at once: clear in par rounds or fewer, land every shot you fired, and finish with zero damage. One miss anywhere and the S is gone for that mission, which is why the green line matters. An A allows one round over par, eighty percent accuracy and at most one hit taken; a B allows three rounds over par and fifty percent accuracy.

Your records live in your browser, on your device: best rank, fewest rounds, best accuracy, fastest clear. They are one set across all four compounds, so a fewest-rounds record will tend to come from a par-four compound. Alongside them runs a streak of consecutive clears, which resets to zero when a mission fails, while your best streak is kept. Sharing a result produces a debrief card plus a link carrying the mission seed — opening it deals the identical compound with identical hostile behaviour, so a friend races your actual run rather than a layout that merely looks like it.

07  How to earn your first S-rank

The S is a discipline problem more than a skill problem. Five habits get most of the way there:

• Plan the move to end outside every arc, not just outside the red wash — a hostile holding a sighting on you pushes forward and carries its arc with it. Breaking the line of sight is better defence than distance.
• Use the doorways. Standing in one blocks every line through it while letting you fire out — the best square on the board, and it costs nothing.
• Aim a tile ahead of a hostile that has already spotted you. It is walking toward your last-seen tile, not holding still, so shoot where it is going.
• Never fire at a red line. The miss is permanent, and the S tolerates exactly zero of them.
• Learn one compound properly, then race your own fewest-rounds number on it. The seed is fixed, so the record is genuinely beatable.

08  Questions people ask

Is Sweepmark free, and do I need an account?

Free, and no account. There is no sign-up, no login, no download and no install — it runs in the browser tab it opens in, supported by unobtrusive ads. Your best ranks and streak are stored in your own browser rather than on a server.

Is Sweepmark like XCOM, Frozen Synapse or Door Kickers?

It is in the same family as Frozen Synapse and Door Kickers — you commit a plan, the enemy commits one blind, and both resolve at once. The difference is scale and cost: those are paid native or Steam titles built around a long campaign, while Sweepmark is one compound, one mission and a few minutes, free in a browser tab with no install.

Is there any luck in Sweepmark, or is it pure skill?

There is no randomness in how a round resolves. Shots are decided by range and line of sight, hostile planning is a pure function of the state, and the same plan always produces the same replay. The only thing chance decides is which of the four compounds a fresh mission deals you.

How do I get an S-rank in Sweepmark?

All three at once: clear in par rounds or fewer, land every shot you fired, and take zero damage. Par is four or five rounds depending on the compound. A single miss ends your S for that run, so the reliable route is to plan moves that end outside every hostile arc and only ever fire on a green line.

Does Sweepmark work on a phone?

Yes. It is built mobile-first — you drag your operator and tap tiles to aim, which works with a thumb in portrait or landscape. It needs to load once over the network, after which the whole simulation runs locally in your browser.

Can I play the exact same compound as a friend?

Yes. Sharing a result gives a link carrying the mission seed, and opening it deals the identical compound with identical hostile behaviour — not a similar-looking board, the same one. That makes a shared result a fair head-to-head rather than two separate attempts.

09  More from the shelf

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