🐛 Inkworm

The classic snake, redrawn in ink

Inkworm is a fresh take on the game everyone already knows: a worm that grows a little longer each time it eats. The rules are simple enough to pick up in a second — move, eat, don't crash — but chasing a high score never really gets old. The board is a tidy 21×21 grid, the worm is a chain of ink squares with a rust-coloured head, and every droplet you catch is one more segment trailing behind you.

Seven steps a second, climbing to eighteen

The worm starts out moving seven squares per second and picks up one more step for every five droplets it swallows, levelling off at eighteen. Nothing else about the board changes: the edges are solid walls rather than wrap-around, so the only thing that moves is you, and the room you have left to turn in shrinks with every segment you gain. Most runs end because a direction was committed to half a second before there was space for it.

Two rules end a run, and one of them gets misread

Only two things kill the worm: the outer wall and its own body. The edges do not wrap, so all four sides are hard. Nothing else on the board can hurt you — the droplets are inert, there is no timer, and the worm never starves.

The self-collision rule is the one people read wrong. The tail tip vacates its square on the same tick the head moves into a new one, so the cell directly behind your last segment is legal: you can follow your own tail around a coil indefinitely and never bite it. The exception is the tick you swallow a droplet. On that tick the worm grows instead of releasing the tail, the old tail cell stays occupied, and the square you had mentally marked as safe is suddenly solid. A surprising share of "unfair" deaths happen exactly there — one cell behind the tail, one tick after eating.

Two input rules are worth knowing for the same reason. A straight 180° reversal is discarded rather than executed, so slapping the opposite arrow in a panic does literally nothing. And only one turn is buffered at a time: press left and then up inside the same tick and the left is thrown away, keeping only the up. A genuine double-turn around a corner has to straddle two ticks, which at top speed means waiting a shade over a tenth of a second between presses.

The speed table

Speed is a pure function of appetite. The worm starts at seven steps per second and gains one more for every five droplets it swallows, stopping at eighteen. Nothing else — not length, not time elapsed, not how close you are to the wall — moves the number.

Each tier is five droplets wide, so the jumps land at 5, 10, 15 … 55.

The useful thing about that table is where it stops. Eighteen arrives at fifty-five droplets — a score of 5,500, and a worm still only fifty-eight segments long on a 441-square board. Everything past that point is played at one unchanging speed. Inkworm is therefore not a difficulty curve so much as a short ramp followed by a very long plateau, and on the plateau the only variable still moving is the length of your own body.

Coiling, and the lane you leave yourself

Because the tail always releases, a long worm is not an obstacle so much as a moving wall with a door in it that opens once per tick. Good play is mostly about knowing where that door is. The standard answer is to coil: run tight parallel lanes back and forth across the board so the body stacks into a predictable slab rather than a tangle. A slab has a front edge you can read at a glance; a tangle has to be traced.

The failure mode a coil protects against is sealing a pocket. If you loop a ring of body around empty squares and the droplet spawns inside it, you have to unwind the whole ring to reach it, and the worm is longer by the time you get there. Droplets appear uniformly at random on any square the worm does not currently occupy, so the board never favours you — which means every pocket you close is a real bet against yourself.

The practical habit is to keep one escape lane open along a wall at all times, and to collect droplets on the way past rather than turning to chase them. Turning to chase costs two turns and usually spends the lane. Sitting at eighteen steps per second, an escape lane is worth more than any single droplet, because the lane is what buys you the half-second of thinking time the speed took away.

Board arithmetic

The grid is 21 by 21, which is 441 squares, and the worm opens at three segments — so a board filled to the last square takes 438 droplets and ends with a "Perfect run!" banner rather than a crash. Since the speed cap lands at droplet fifty-five, roughly seven eighths of a maximal run happens at exactly eighteen steps per second.

Your best score lives in this browser's local storage under the key kp_inkworm_best and is the only thing the game keeps on its own. The leaderboard is separate and deliberate: nothing is sent anywhere until you type a name on the game-over card and press Post, which writes a single record — the game id, that name, that score and a server timestamp. If the leaderboard's code fails to load, the game plays exactly the same and only the online board goes quiet.