Move: arrow keys (hold to keep walking), or swipe / tap a cell to walk to it. You will die on the spikes; your body sheathes them so the next you walks over it. Bridge the gap and jam the crusher with your dead, then reach the exit. Pips count the turns until a trap fires. Need one to pass? Wait 2 turns (Space, held for more) steps you one cell aside and straight back, so you finish on the square you started on with every trap two beats further on. Fewest bodies wins. Each body is ringed with what it bought: green = route open, red dashed = still kills, grey dotted = bought nothing. Fumbled a step? Z (or the Undo step button) takes back your last living step and its move — deaths stand, the corpse stays, and the clock never rewinds. Take back rewinds to just before a chosen body died, earlier ones kept, mid-room. Spent a body in the wrong place? Take back a body (or B) rewinds the room to the step before that body died and keeps every body before it — while you are still playing, not only on a clear. The active clock counts play time only: a backgrounded tab accrues none. R fresh board · T theme · M sound. B take back a body.
The clock counts active play only: it starts on your first committed step and pauses while this tab is in the background, so a backgrounded tab accrues no time (nor does a page you loaded and never moved on). Undo takes back a move, never a death, and never rewinds the clock — moves drop by one, deaths do not move, and the seconds you already spent stay spent. Deaths and moves are re-derived by replaying your stored input tape through the sim, so a reload reproduces them exactly; moves counts every step the skeleton took, including the ones the post-death auto-resume replayed for you, and deaths is the same number as the bodies counter.
Dead Weight is a turn-based grid dungeon in which every death leaves a corpse exactly where you fell, and that corpse stays on the board for the rest of the attempt. A body dropped into a pit bridges it and a body dropped on a spike row sheathes it, both immediately and permanently, so the next skeleton walks straight over. A crusher is the slower trade: the corpse under the ram is not safe to stand on until the ram has slammed down on it twice, and only then does it jam open for good. So you are not trying to survive the room, you are spending bodies to open a route to the exit, and the page keeps your cheapest clear of that specific room as a stored best clear in bodies.
On a phone it is one thumb: swipe in a direction to take a single step, or tap any cell in your row or column to walk to it in a straight line. A tap resolves to whichever axis you aimed further along, and it never turns a corner and never routes around a wall — the routing is the puzzle and every turn is still yours to make. What it removes is the typing: clearing level 1 takes at least 29 steps but only 14 inputs, and level 25 takes 97 steps and 38 inputs. A walk stops the instant anything happens — at a wall, on the exit, and one cell short of anything that would kill you — so it can never spend a body you did not choose. To make a corpse you step in from right beside it, which is one press exactly as it always was. A walk spends one turn per cell, so a six-cell tap hands the board back six turns later with every trap six beats on — but nothing moves until you do, so there is still no clock in it and no reflex to fail: the pips under a trap count the turns left before it fires, and they sit still while you think. When the thing in your way is a beat rather than a wall, the Wait control under the board turns a dozen idle presses into one: it spends two turns and hands the board back with every trap two beats further on, so a crusher on a six-beat period still crushes. It says two because it costs two. Nothing in this sim can spend a turn and leave a body standing where it is — every accepted move costs one cell and one tick — so a wait is one step aside and one step straight back: two real moves, two ticks, and two undos, landing you on the square you set off from. It is asked of the same pure sim a walk is asked of, one step at a time, so it can never carry you into a cell that would kill you and can never shuffle you onto the exit, and it is dimmed whenever there is no next-door square you could step into and come straight back from. On a desktop the arrow keys or WASD take a step and holding one down keeps walking under that same rule, the space bar waits and holding it keeps waiting, Z or Backspace takes back your last living step — one cell at a time, so a six-cell walk is six undos — R resets the room, T flips light and dark, M mutes the sound, and ? hides or shows the how-to line, which sits under the board on a phone and in a column beside it on a wide landscape screen.
There are twenty-five levels in one frozen order: the same twenty-five rooms, in the same order, for every player, forever, so that two people’s times on level 4 are times on the same room. A bare URL is level 1, and ?level=N opens any of the twenty-five. They escalate on a stated mechanical measure rather than a measured difficulty curve — the solver-proven minimum body count first, then how badly a memoryless walker that just steps toward the exit does — so levels 1 to 6 can all be cleared with 2 bodies, levels 7 to 13 with 3, levels 14 to 16 with 4, levels 17, 18 and 19 with 5, levels 20 and 21 with 6, level 22 with 7 and levels 23, 24 and 25 with 8, while that naive walker spends 5 bodies on level 1 and 12 on levels 22 and 25, the two rooms that cost the most for a player who never stops to count. The second measure is not monotone and is not presented as one: it restarts whenever the minimum steps up, which is why level 17 sits at 7 rather than above level 16's 11, and why level 20 sits at 9 rather than above level 19’s 11 — and then climbs again inside each new tier, 7 to 9 to 11 across levels 17, 18 and 19 and 9 to 11 across levels 20 and 21. Levels 1 to 12 are generated from a seed rather than hand-built, and every room that generator ever produced is still addressable: ?day=YYYY-MM-DD rebuilds the room for any date from 2020-01-01 to 2099-12-31. That is a secondary mode — ?day= is only read when no ?level= is present, and because a date replay is not a rung on the ladder the share button is hidden there. Levels 13 to 25 are the thirteen rooms placed by hand, cell by cell, because each is built around a rule the generator has no way to express: the pressure plate and its door on 13, 14, 15, 17, 18, 19, 20, 21, 22, 23 and 25, and the slippery floor on 16, 17, 19, 21, 23 and 24, where a body that steps onto ice keeps going until something that is not ice stops it. Levels 18 and 19 are the two rooms built up and down rather than along — 18 stands five one-cell chimneys on top of its road, because both of its rams sit wedged between pits and there is nowhere on the road itself to wait out a beat, and 19 turns the road into a ceiling and hangs four ice shafts under it, so a single step downwards carries you eight rows to a cellar floor. Levels 20 and 21 stop introducing rules and start stacking them: 20 puts two rams a single cell apart with stone above and below the cell between them, so there is nowhere to pause mid-crossing and one step has to be right for both hammers at once, and 21 seals each door’s plate at the bottom of a five-cell ice shaft, so — since you can never come to rest on ice — the only way to open a door is to post a body down the slot and let the slide finish the job. The last four are the first rooms that ask you to work something out before you can execute anything. 22 stands three rams side by side with no cell between them and stone above and below all three, and no tick clears the run of three, so the only way past is to give one hammer a body and then leave it alone long enough for that hammer to strike the corpse twice — a corpse under a ram bridges nothing until it has been hit twice, unlike a corpse in a pit, which bridges it the instant it lands — and the middle hammer is the one that buys nothing at all. 23 asks the question all four earlier ice rooms answered for you: where can you stand on ice? Only where the cell ahead refuses you, and the only refusals on its single long lane are two doors nobody has paid for yet, so each shut door is the one place you can stop, and therefore the one place you can turn, on its half of the lane — and the plate that opens that door hangs directly off the turn it makes. 24 holds that 8-body par and changes the currency. Every accepted move costs one cell and one tick — including each cell of a slide — so the parity of the clock is pinned to the chequerboard, and no amount of waiting or doubling back can change it: a round trip is always an even number of steps. The one thing that can change it is a death, because the corpse stays where it fell and the next body starts back at the spawn. The two rams at the far end are welded together by a two-cell slide that samples the second exactly three ticks after the first, and that odd number leaves a single beat in four that opens both — a beat the first body can never be standing on. Two of the eight deaths the room forces land on squares an odd walk from the spawn, so the four pit-walls that have a mouth on the gantry as well as on the road have to be paid down on the road an odd number of times: one of the four, or three. Both tidy lines are wrong — walk the road and pay every wall where you meet it, which is what every earlier gantry room rewards, and the far end never opens at all; take the gantry the whole way and it stays just as shut. 25 holds that same 8-body par and asks a plainer question that is easy to not ask. It has six pit-walls, more than any other room on the ladder, and it runs a cellar under the first half of the row. At three of the four barriers over that cellar the two mouths are true twins — pit above, pit below, one body whichever one you drop into, which is exactly what every earlier two-storey room trains you to expect. At the fourth there is stone under the pit, so the row pays a body there and the cellar walks under it, and nothing on the board says which of the four it is. The other half of the room is a tollbooth built the awkward way round: the door in the middle is opened from a sump directly beneath the pit in front of it, and the sump can only be reached from that pit, so the pit has to be bridged before the plate can be pressed — the only column in the room that takes two corpses, and it takes them in every one of the eight cheapest solutions the solver finds. Flatten all three of its timed hazards to plain floor and the minimum does not move at all, while the naive walker's cost falls from 12 to 9: the clocks price a blunderer and are not the question. The insight is worth exactly one body — a player who never looks down still clears the room, at 9.
Level 13 has a pressure pit one step below the corridor, and its weight holds a door four cells away open. The pit kills you exactly like any other hole and your corpse bridges it exactly like any other hole — but while that corpse lies in it, the door stops being a wall, and because corpses are never removed the door stays open for the rest of the attempt. There is no way round it: the exit chamber has one entrance. So the solver-proven minimum is three bodies and the third is a pure toll — it bridges nothing you need, it buys the door and nothing else. The other two go into the two full-height pit-walls that cut the room in thirds, and which of their openings you fall into is the real choice: commit to the top lane or the bottom lane and the shortest clear is 39 moves, change your mind halfway across and the same three corpses cost 51. That 12-move penalty is the whole point on a ladder built for comparable times. The naive walker that only ever steps toward the exit spends eleven bodies here, and its ninth is the mechanic teaching itself — it reaches the tile beside the shut door, finds nowhere better to go, steps sideways into the hole, and the door it could not open swings open as the body lands.
Level 14 puts two of those doors in series. The first pressure pit opens a door, and behind that door is nothing but the second pressure pit, which opens the door to the exit — so two of the four bodies the solver needs are tolls that bridge nothing, and neither can be paid early or out of order, because the only cell next to the second pit is the one the first door leads into. The other two bodies go into the two gap-walls at the left of the room, and here the lanes are not interchangeable the way level 13's are: the low road is the cheapest line in the room at 68 moves, because the pocket you drop into behind the low crossing has no way out except the pressure pit itself, so one corpse both frees you and opens the door. The top road costs 72, and changing lanes halfway costs 92 or 96. Two more things are new: the two spikes in the side lanes are the first traps in the game that are not on the corridor row, and there is a plain hole directly opposite the first plate — a body in that one buys literally nothing. Plates are drawn as a pit with an amber ring and a chevron pointing at the door they work, so it is a test of looking rather than a guess, but it will cost a body the first time.
Level 15 turns the door rule inside out. On levels 13 and 14 a pressure pit is a tollbooth — the body you drop in it buys the door and nothing else. Level 15 sets one of its pressure pits into a wall you have to cross anyway: it is one of the two mouths of the third pit-wall, and the other mouth is a plain hole two rows up on the corridor. Both cost exactly one body, and only one of them also opens the door twelve cells away, so that corpse is the plank and the key at once. The old answer is still on the board and still works — a plate in an alcove beside the door, which is the one the naive walker finds, and which costs a fifth body. The front of the room is a chasm two full-height pit-walls thick, the first on the ladder that needs two corpses to bridge, and you throw the second one in while standing on the first. The corridor row is the trap: straight ahead the chasm is three cells wide rather than two, and both chamber floors have a hole in them on that row, which is why the memoryless walker spends ten bodies here against the solver's four. The cheapest of the four minimum lines is the low road at 59 moves, because the plate in the wall is on the bottom lane; cross high and the same four corpses cost 71, change lanes mid-room and they cost 77 or 89.
Ice is a floor you cannot stop on. A step that lands on ice does not end there: you keep going in the direction you pressed, one cell per tick, until the next cell is a wall, a shut door or the edge of the grid, or until you reach a cell that is not ice — and you come to rest on that one. It is never lethal and it never holds a body, so no corpse can ever be left on it; what ice takes away is not your life, it is your choice of where to spend it. Level 16 is ice on its own: two lanes of it with a few ordinary floor cells set in as landings, and the rule that follows is that you can only start a slide from solid ground, so the lane you enter a chamber by is usually the lane you have to leave by. Four pit-walls, four bodies, and the shortest minimum-body clear the solver finds is 32 moves. The memoryless walker spends eleven bodies there, tying the worst on the ladder, and it never once touches the ice — the straight line to the exit runs two rows away from both lanes, which is a fair warning that eleven measures how bad the corridor is and not how well the ice reads. Level 17 puts ice against the two rules you already know. A skid ends on a crusher, and because a slide spends a tick per cell the ram keeps beating while you travel and is checked at the tick you arrive, so the only thing you control is the beat you launch on — you cannot slow down halfway. And a shut door stops a skid dead while an open one lets it through, so the same single input either slams you to a halt on the last patch of ice or carries you through the doorway. Five bodies, 28 moves, and one road: the plate that opens the door sits ten cells before it, and the second plate beside the door can only be reached when the door is still shut, because once it opens that cell stops being anywhere you can stand. Level 19 is the third ice room and the first that pushes ice downwards: its road is the ceiling of the level, and four shafts of ice hang under it, seven cells deep. Stepping down into one is a lift — one input carries you eight rows, seven of them ice, and sets you down on the cellar floor — but the ride back up ends where the shaft began, and two of the four shafts begin on a crusher, so going down is always free and coming up is sometimes a beat you had to count. Every one of the three walls in that room has a mouth on the road and a second mouth on the cellar floor, so both storeys cost the same single body and there are eight different five-body solutions, the most of any room here. Level 21 is the fourth and last, and it uses ice for something none of the others do: instead of moving you somewhere, it spends you. Both of its pressure plates sit at the bottom of a five-cell ice shaft with nothing beside them a body can stand on, so there is no way to step onto a plate the way you could on every earlier rung — you stand on the mouth of the shaft, press down once, and the slide delivers a skeleton five cells later onto the plate that opens the door. That is the whole toll: you cannot call the slide off at cell three, and you cannot pay any other way.
The clock counts active play only: it starts on your first committed step and pauses while the tab is in the background, so a backgrounded tab accrues no time, and neither does a page you loaded and never moved on. Undo takes back a move, never a death, and never rewinds the clock — moves drop by one, deaths do not move, and the seconds you already spent stay spent. Deaths and moves are never counted into a variable; they are re-derived by replaying your stored input tape through the sim, so a reload reproduces them exactly, and moves counts every step the skeleton took, including the ones the post-death auto-resume replayed for you. Each level you clear also goes into a cumulative ladder run shown above the board — one record per rung, kept on fewest deaths first and fastest time second, with the whole-ladder totals added up from those per-level bests, which makes the total a best-segments figure rather than a time anyone necessarily played end to end. That run is stored in this browser under a single localStorage key and nowhere else: no account, no server, no leaderboard, and clearing your site data (or pressing Reset run and confirming) erases it.
Clear a ladder level, press Share this clear, and the page copies two lines: a result strip that reads DEAD WEIGHT lvl 4/25 · cleared · 1:12 · 💀💀💀 3 deaths · 27 moves, and an absolute link ending in ?r= followed by a code that carries your actual input tape. Whoever opens that link lands on the same level, and the page replays your tape through the same sim to re-derive the deaths and moves instead of trusting the numbers in the link; if the tape does not clear that room the result is refused and the page names the check that failed. The elapsed time is the one number that cannot be re-derived, so it travels as a self-reported claim, and there is no account, no server and no leaderboard — comparing two runs means sending someone the link.