Straight to the point: Butterfly Mode is gaps that start at 47% of the screen and shrink with every point, playable in your browser right now. It is tuned for quick runs, honest difficulty, and controls that make sense the first time you touch them.
One tap flaps, releasing drops, and the world scrolls at you; thread the gaps and keep off the ground and the ceiling. The gaps that start at 47% of the screen and shrink with every point, so early pipes feel generous and the run only gets sharper the longer you survive.
Nothing here needs a tutorial or a wiki. Controls are one gesture, the goal is one sentence, and the difficulty comes from execution rather than homework. That is exactly what a browser game should be.
Flap through the pipes. One tap, one life, endless sky.
Butterfly Mode is filed under Pecut Shelf, and the decision comes down to one tag set: arcade, one-tap, endless. Those three words are the whole reason it is not sitting somewhere else.
Difficulty sits at Easy and the player count at 1. Those two numbers decide more about whether you will enjoy it than the theme does.
The companion game to try afterwards is Calm Wings: same family, different emphasis, and together they show what the Pecut Shelf is actually good at.