Traffic

Every entry in the js13kGames competition has to fit inside a 13-kilobyte zip file, which tends to produce either scrappy tech demos or, occasionally, something genuinely tight and well-made because there was no room left for anything unnecessary. Traffic is the second kind. You watch over an isometric city — Paris to start, five more to unlock — where cars stream through intersections and your only tool is tapping a crossroad to flip its lights. Let too many drivers sit too long and their collective "anger level" ends the round. It's a small, clear idea executed with real polish: working turn signals on the cars, a day/night cycle with its own lighting pass, six distinct city layouts rather than one map reused six times. The result placed 2nd in js13kGames 2013's Mobile category, and played today, that result still holds up.

A one-line bug, confirmed and fixed

The candidate arrived with a real, measurable problem rather than a vague "might not work on mobile" concern. Its viewport meta tag read user-scalable=no with no width=device-width directive, and measuring the rendered canvas directly on a simulated phone confirmed the consequence: the browser fell back to treating the page as if it were roughly 980 CSS pixels wide — the legacy default many mobile browsers use for pages that don't explicitly declare a mobile-aware viewport — rather than the phone's actual ~390-pixel width. Because user-scalable=no also blocks pinch-zoom, there would have been no way for a player to compensate by zooming in. Adding width=device-width, initial-scale=1 to the meta tag and re-measuring confirmed the fix: the canvas correctly reports and renders at the device's real width afterward, with the game's own engine.scaleToFit calculation then working exactly as its author intended.

That calculation, once it has correct inputs, is worth crediting on its own: windowResized() computes a scale factor from the true viewport dimensions and applies it via a CSS transform, and the touch handler divides incoming touch coordinates by that same factor before checking which intersection was tapped. That symmetry is why the fix was a pure viewport-tag correction rather than anything touching the game's own logic — the underlying math was already right, it just never received accurate numbers to work with. Confirmed by testing in the game's clearly intended landscape orientation, a tap on a specific intersection produced a visible white highlight box at exactly that intersection before the light flipped, with the resulting green light appearing precisely where expected. The same interaction still works with a smaller board in portrait, since the underlying scale-to-fit correction applies regardless of orientation.

Small, but not thin

Six cities, each with a genuinely different road layout rather than a palette swap, is more content than a lot of jam games bother with. The anger-level pressure system gives the light- flipping loop actual stakes rather than being a static puzzle, and the day/night toggle changes the lighting pass rather than just tinting the screen. None of this is complicated, but all of it is deliberate, and it adds up to something with real replay pull for anyone who likes optimization-under-pressure arcade games.

Where that leaves it

An 8.0 reflects a genuinely well-built, competitively-recognized small game that needed exactly one line changed to work correctly on the device category this shelf cares most about — confirmed by direct measurement, not assumed. Recommended, and best played with the phone turned to landscape, the way its own orientation-handling code clearly expects.