Tap Flyer

How Tap Flyer works

There is one input and one rule. Tapping lifts you; letting go does nothing, because gravity is always pulling you down. A stream of pillars comes at you from the right, each with a gap in it, and your job is to be level with the gap when you arrive. Touch a pillar or the ground and the run is over.

That is the whole game, and the reason it is worth playing is that a single input turns out to be surprisingly hard to aim. A tap does not nudge you — it replaces your vertical speed outright, throwing you upward at a fixed rate. So the skill is not in tapping harder or softer, which you cannot do; it is in tapping at the right moment, and in reading how far you will drift before the next one.

You cannot fly off the top. The ceiling holds you rather than ending the run, so pinning yourself up there is a mistake you can recover from — though not a useful place to be, since the gaps are rarely at the very top and you will have a long way to fall.

Fullscreen blows the field up to fill your screen, with nothing around it that a drifting tap could scroll; the course itself stays the same size, so the game plays exactly as it does on the page. Press Escape or Exit to leave it.

How the course is built

The pillars are generated rather than drawn from a fixed list, so a run never repeats and never runs out. Two things ramp up as you go:

• The gap shrinks. It starts at 172 pixels and loses a little with each pillar, reaching its floor of 108 at the twentieth. It never gets tighter than that.
• The course speeds up. It starts at 130 pixels a second and climbs to a ceiling of 230. The pillars are a fixed distance apart, so this shows up as less time to think: 1.54 seconds between pillars at the start, 0.87 at full speed.

The first pillar is deliberately far out — a little over three seconds of clear sky on every run, so nobody dies to something they had no time to see.

Every course is flyable

The gaps do not jump around at random. A gap's position follows two slow waves rather than being drawn independently each time, and that is a fairness decision rather than an aesthetic one.

Here is the arithmetic behind it. Tapping as fast as is useful climbs about 215 pixels a second. At full speed the pillars are 0.87 seconds apart, so the most you can climb between two of them is around 187 pixels. An independent draw could easily put consecutive gaps 280 pixels apart — and a run that ends there did not end because you were bad at it, it ended because it could not be flown. The waves hold the change under 84 pixels, comfortably inside what a tap can cover, and a test asserts that bound rather than trusting the design.

So every course can be flown indefinitely by a good enough pilot. That is checked, not assumed: a search over the actual simulation flies every seed tried for three solid minutes, past the point where the gap has reached its floor and the speed its ceiling.

Why it plays the same everywhere

The simulation advances in fixed steps of one sixtieth of a second, and the drawing interpolates between them. This is why the game feels identical on a 60 Hz laptop and a 120 Hz phone, rather than being twice as hard on one of them — and it is what makes a run reproducible from its seed and the moments you tapped.

There is one more guard worth knowing about. Browsers stop animating a tab you have switched away from, so coming back hands the game however long you were gone as a single frame. Unclamped, that would drop the flyer straight through the course while you were looking at something else. The step a single frame may take is capped, so switching tabs costs you nothing.

Motion, and playing without it

If your system asks for reduced motion, the drifting background stops moving. The pillars and the flyer do not, because they are the game rather than decoration — pinning those would not be a gentler version of Tap Flyer, it would be no game at all. What goes away is the parallax that exists purely to make the field feel fast.

Everything runs in your browser. Your best score is saved locally, nothing is uploaded, there are no accounts, and the whole thing works offline once the page has loaded.

Where the game comes from

This is the Flappy Bird mechanic, published by Dong Nguyen in 2013 and briefly the most downloaded game in the world. The rules of a game are not something anyone owns, but a game's title and its look are: the name, the bird and the green pipes are all his. None of them are reproduced here. What you get is the mechanic, drawn in this site's own colours.