The visual read is beautifully clean. Field green, white line, white ball, jagged white spikes, a red Start band. You understand the entire scene without a word of text, which is rarer in this jam than it should be.
And the title is a good bit of thinking: a golf game with no flag, meaning there's no end, only getting higher than last time. That's the jam's theme in two words. Once I understood the gesture the shot felt satisfying too, the white aim line coming off the ball as you drag, and the camera rising with you as you gain height.
The blocker: the shot power seems to be capped. I tested drags of 200px, 400px and one nearly the full height of the screen (710px), and the ball went up almost exactly the same distance all three times, always falling back to the start. I never got past the Start band. I'm not the only one, there's a comment on your page saying exactly this, that they can't progress and the force applied to the ball could probably be higher.
You also flag in the description that the game LOSES MOUSE INPUT if you drag outside the play area, and that it only works properly in fullscreen. I can confirm: when my drag ended outside the canvas, the aim line froze on screen and the shot never fired. Since the game's core gesture is dragging a long way, that happens constantly. Capturing the pointer while the mouse is held down would fix it.
Two smaller ones. The gesture isn't explained anywhere in the game. People in your comments assumed you had to drag FROM the ball (I did too) when actually you can drag from anywhere and only the direction matters. A three second animated arrow on the first screen would solve that for everyone at once. And the title on the start screen is partly hidden behind the grass texture, I could only read "N. Fl.ag ...ole?".
The core is good and it looks nice. More power and locking the mouse to the window would fix almost everything.