About the 50 Metre Swim
Swimming fast is about rhythm, not thrashing, and this event is built to make that point. One length of the pool, fifty metres, powered by how well you keep time.
How it works
At the bottom of the screen is a meter with a yellow zone in the middle. A white marker sweeps from one end to the other and back, crossing the zone on every pass.
Tap while the marker is in the yellow and your swimmer takes a proper stroke. Catch it right in the centre and the game calls it "Perfect", with an extra surge. Tap outside the zone and you get a "Splash": a weak stroke that barely moves you.
The swimmer is always slowing down between strokes, so you need to keep them coming. You cannot simply hammer the screen, though. Taps that follow too closely on each other are ignored.
Swimming a faster length
Tap on every pass. The marker crosses the centre of the zone twice in each full sweep, once going each way. Take both.
Aim for the middle. A Perfect is worth nearly a third more than a Good. Over a whole length, that adds up to several seconds.
Listen to the rhythm in your head. The marker moves at a constant rate, so the right moments come at perfectly even intervals. After the first few strokes, tap to the beat, and use your eyes only to check.
Do not chase a missed stroke. If you tap late and get a splash, wait for the next pass. A second, panicked tap will be out of time as well.
Stay relaxed. Tense fingers tap early.
A length of nothing but Perfects is comfortably inside the gold time. As rhythm-based HTML5 games go, it is a calm one, right up until the last five metres.