Tap / click / press Space to fly. The gap drifts up and down as each pipe approaches, time your flight to where it will be, not where it is now. Pass a gap to score 1 point.
Everyone knows how to play Flappy Neon in about five seconds. What they don't expect is the gap drifting up and down as each pipe rolls in, so the spot you're aiming for isn't where it'll actually be when you get there. Free, no download, and scoring past 10 is rare.