The atmosphere is pretty and calm. Light blue sky with clouds, a dark grid platform stretching to the horizon, and dozens of translucent balloons drifting up in blue, white and pink. It has a genuinely contemplative mood, which is unusual in a jam full of neon and noise. The character is a round, chubby low poly creature in a helmet, half ridiculous and half cute, and it works. The 10 / 10 ammo counter in the corner is big and clear too.
But I couldn't actually play it. PLAY only responded to a double click, and once I was in, I couldn't shoot at all. I clicked on plenty of balloons and the ammo stayed at 10/10 with nothing popping.
The bigger bug: the counter reads "Score :" with no number after the colon. It looks like the variable isn't being written to the screen, and in a high score game that's the worst possible place for a bug, because the score is the entire point.
Two smaller things. There's a solid white square in the bottom left corner with nothing in it, which looks like a missing texture or a minimap placeholder. And the browser tab says "Projects_Template", the default Unity project name. That last one is 30 seconds of work and it changes the first impression a lot.
The scene is genuinely nice to look at. Get the shooting and the score display working and there's something here worth voting on properly. One thought on the end of life answer as well, since that's a scored criterion here: "it will stay as a WebGL build on itch.io" leaves the game entirely dependent on itch staying up. A downloadable build would cover you.