Pulse Lock — At Length

Pulse Lock is our highest-rated game in Issue One at 4.7 out of 5. The original review covers what it is and how to play; this article is the longer version — why we think it deserves the top score, what the design choices were behind it, and the small details that elevate it from "competent timing game" to something we are genuinely proud of.

The core loop

Pulse Lock is a single-screen game with one interaction: a marker sweeps back and forth across a fixed line, and you tap to lock it as it crosses a target zone. The closer to the zone's centre, the higher your score. The zone shrinks slightly with each successful lock. After ten locks, the zone is small enough that perfect timing matters; after twenty, the game is genuinely difficult.

What makes this loop work — and what most one-button timing games get wrong — is the sweep speed. Too fast and the game is pure reaction, which is unsustainable and frustrating. Too slow and the game is trivial, with no meaningful pressure. Pulse Lock's sweep starts at a speed that allows comfortable reaction (you can see the marker approach the zone and respond), but the zone shrinks faster than the sweep slows, which means by lock ten you can no longer rely on reaction — you have to start predicting. The transition from reaction to prediction is the entire game.

The 200-millisecond truth

Human visual reaction time is roughly 200 milliseconds — a tenth of a second to see something, plus another tenth to issue a motor response. In Pulse Lock's late game, the marker crosses the target zone in less than 200 milliseconds. This is not coincidence; it is the point. By the time you visually confirm the marker has reached the zone, it has already passed. The only way to succeed is to act before visual confirmation, which means predicting where the marker will be one or two frames ahead based on its observed motion.

This is the same skill a baseball batter uses to hit a fastball, a tennis player uses to return a serve, or a drummer uses to play to a click track. All three operate below the threshold of conscious reaction; all three rely on prediction from a brief observation of the incoming signal. Pulse Lock is a low-effort, low-stakes way to practise this skill in your browser. We did not set out to make a training tool — but the game accidentally became one.

The scoring curve

The scoring curve in Pulse Lock is steeper than it needs to be, and that was deliberate. A perfect lock — within roughly 5% of the zone centre — scores 100 points. A merely good lock — within 25% — scores 30. A barely successful lock — touching the zone at all — scores 10. The ratio between perfect and barely is 10x, not 3x, which means players who chase perfection consistently outscore players who chase consistency.

This shaped the game's culture. Players who pull up a leaderboard see a clear distinction between "I played 100 rounds, did okay each time" and "I played 50 rounds, nailed every one". The latter wins comfortably. The scoring curve makes the cost of imperfection visible.

The single design choice we agonised over

Pulse Lock has one variable we adjusted dozens of times in playtesting: the deceleration profile when a lock succeeds. After a successful lock, the marker pauses briefly before resuming. How brief? Too short and the game feels relentless; too long and momentum stalls. We settled on roughly 400 milliseconds, which is long enough for the player to register the success but short enough that the game's tempo never breaks. This single number, more than any other, made Pulse Lock feel like Pulse Lock.

It is the kind of detail nobody notices when it is right. We bring it up because we think the difference between a 4.0 game and a 4.7 game is often a handful of these invisible decisions — and getting them right requires playtesting your own game more than is comfortable. We played Pulse Lock several hundred times during development. By the end, we could feel a 50-millisecond change in the deceleration. That sensitivity is what tuning a game well requires.

Where it does not work

Pulse Lock has one honest weakness: a single-button game has a short ceiling on how long it can hold a session. After about ten minutes, even an excellent one-button game starts to feel repetitive. We are aware of this and chose not to address it — adding variety would have meant adding rules, which would have moved the game away from its central virtue, which is purity. Pulse Lock is a five-to-eight-minute game. We made it the best five-to-eight-minute game we could, and we did not try to make it more.

Published · 14 May 2026 · Written and signed by Bill