Swing on a vine, tap to let go, then tap again to grab the next vine. Don't hit the ground.
You start hanging from a vine that swings you back and forth like a pendulum. Tap anywhere on the screen to let go — your speed at the moment you release becomes your flight speed.
While flying, gravity pulls you down. New vines hang from the canopy ahead. Tap again when you're close to one to swing your arm and grab it. If you're too far the grab misses and you keep falling.
Let go too early and you don't have enough horizontal speed. Hold on too long and the vine swings back before you leave. The best release is on the way up, just after the bottom of the forward swing — roughly when the vine leans 20 to 40 degrees forward — so you fly outward and upward instead of flat.
The vines get further apart as you progress, with no upper limit — sooner or later a gap is too wide for any swing, so the question is how far you get. Hitting the ground ends the run.
Goal: grab as many vines as you can.
The bottom of the swing is where you move fastest, but letting go there sends you out flat and you start falling at once. Waiting a moment longer, until the vine leans forward on the upswing, trades a little speed for an upward launch angle, and that carries you much further. Practise letting go when the vine leans roughly a quarter of the way toward horizontal; on longer gaps, wait a touch more.
Look ahead, not at your current vine. As soon as you release you should already know which spot the next vine occupies, because while in the air your only decision is when to tap for the grab. A late grab tap is a soft death — you'll slip past and gravity will finish the job — while a slightly early tap usually still snaps you on because the grab radius is forgiving. When in doubt, tap a beat early rather than a beat late.