Quite an innovative spin on on the horizontal shmup. Different enough to be its own thing. There's a lot going on here, with needing to time jumps to attack and evade, as well as maneuver in the face of the wind.
Very polished and fun!
I instantly guessed that since the only thing you can do is move and jump, that the jump might be a Mario-type attack (since there are no platforms to jump onto, it's probably for the enemies). However, since many players were confused, you might want to start the game with a scripted player character jump in from offscreen and stomp an enemy before the player gains control. Personally, I feel on a game with such basic controls and gameplay, it's fine to let players figure stuff out for themselves, since eventually they will.
The player's respawn feels too slow.
The invincible enemy at the end is slightly unfair, because the game teaches the player to stomp on enemies throughout, but then changes the rules at the end with an enemy that kills the player when stomped on. Every player will definitely die at least once by stomping that enemy, and it's not fair to die from doing exactly what the game has been training them to do. It would be more fair if the player bounced off the enemy without dealing damage, but also didn't die.
The game is only somewhat chaotic, since all the enemies move and shoot in easily predictable ways. If all the action on the screen can be easily processed by the human mind, it doesn't feel chaotic.