Games / 2026 / Live in the browser
Antiphon
A one-button call-and-response rhythm game. The song plays a phrase, you tap it back a bar later, and every tap plays the next note of the melody. Three seeded tracks, judged against the moment each sound reached your ears.
01
The problem
One-button rhythm games usually scroll notes toward a line, so the player reads instead of listening. I wanted the music itself to be the chart: hear a phrase once, then play it back. That needs songs where every answer is exactly the call shifted by a bar, difficulty that comes from rhythm and memory rather than speed alone, and timing judged against what the player actually heard rather than when the key handler ran.
02
How I approached it
A DOM-free UMD engine composes each song from a seed. Rhythms are drawn from a 16-step grid with weights for downbeats, off-beat eighths and sixteenths that ramp up over the song under a minimum note gap, and the melody is a weighted random walk on the track's scale that favours the current chord. The same pass writes drums, bass, pads and count-in as one event list, which a 25 ms timer books 150 ms ahead on the Web Audio clock. Taps are mapped from the event timeStamp onto the audio clock with getOutputTimestamp, which includes output latency, and a calibration screen measures the rest as a median offset. A tap takes the nearest open note within 130 ms, and a tap that hits nothing inside an answer bar is a stray that counts against accuracy. Lantern keeps the call on the dial while you answer, Tidewire fades it after a beat and Glasswork hides it.
03
The outcome
Three tracks at 84, 108 and 132 bpm, remixable to any seed, with early, late and perfect feedback on every tap, a live hit-error meter and a results screen with a 10 ms offset histogram and a per-phrase breakdown. 13 tests with no dependencies cover the one-bar echo for every note, grid and gap rules over 30 seeds per track, judgement windows, nearest-note matching, strays, scoring and calibration. A bot player scores S with 12 ms of timing error and F when it mashes every sixteenth.
Related work
Black Box, the deduction game, with a live count of every atom layout that still fits the rays you have fired. Each board is generated from a seed and proven to have exactly one answer.
A platformer with no jump and no walking. The only control is choosing which way is down, plus one flip in mid-air that comes back when you land. Ten rooms, each proven finishable by a replayed route.
A pipe-routing puzzle played against a rising flow where every open arm floods. Levels are grown from seeded random spanning trees, so each one has a guaranteed route and a retry comes back identical.