Thanks for your detailed description of the gameplay and your feedback!
For the sound, I should have noted it in the description of the submission. The only sound in the game was during the beach scene in the day. Thanks for telling me about the bug in the volume slider.
I did note the controls in the description of the game on the webpage, and in the settings menu, but it would be a good idea to add some instructions to the beginning of the game.
The fireworks were a coincidence, I thought it would be a nice scene to have at the end of the game when it became night time.