Thank you so much for your Feedback!
Yeah you are right, I probably should have added a tutorial, if I had more time. The overcrowd-meter actually works, but you need around 40+ sandCastles on the screen to lose, which many players will never reach, because I think many players don't wait. I initially wanted the game to be played in 2 ways: Safe (= destroy sandCastles instantly, but you don't get additional combo points) and risky (wait and destroy multiple sandCastles at once to earn additional combo points, but you run the risk of overcrowding the beach and lose if you are not careful). I should have made this more obvious, so thanks again for your feedback. (The music is self made by the way, so I'm glad you liked it.)
I'm so happy to get valuable feedback like this and continue developing this game, so thank you! :)